ice_dyn_vp: remove unused subroutine and cleanup interfaces

The previous commit removed the last caller of 'calc_L2norm_squared'.
Remove the subroutine.

Also, do not compute 'sum_squared' in 'residual_vec', since the variable
'L2norm' which receives this value is also unused in 'anderson_solver'
since the previous commit.  Adjust the interface accordingly.

cicecore/cicedynB/dynamics/ice_dyn_vp.F90

@@ -897,8 +897,7 @@ subroutine anderson_solver (icellt  , icellu , &
                                indxui     (:,iblk), indxuj    (:,iblk), &
                                bx       (:,:,iblk), by      (:,:,iblk), &
                                Au       (:,:,iblk), Av      (:,:,iblk), &
-                               Fx       (:,:,iblk), Fy      (:,:,iblk), &
-                               L2norm       (iblk))
+                               Fx       (:,:,iblk), Fy      (:,:,iblk))
          enddo
          !$OMP END PARALLEL DO
          nlres_norm = sqrt(global_sum_prod(Fx(:,:,:), Fx(:,:,:), distrb_info, field_loc_NEcorner) + &
@@ -1959,8 +1958,7 @@ subroutine residual_vec (nx_block   , ny_block, &
                                indxui     , indxuj  , &
                                bx         , by      , &
                                Au         , Av      , &
-                               Fx         , Fy      , &
-                               sum_squared)
+                               Fx         , Fy        )
 
       integer (kind=int_kind), intent(in) :: &
          nx_block, ny_block, & ! block dimensions
@@ -1980,9 +1978,6 @@ subroutine residual_vec (nx_block   , ny_block, &
          Fx      , & ! x residual vector, Fx = bx - Au (N/m^2)
          Fy          ! y residual vector, Fy = by - Av (N/m^2)
 
-      real (kind=dbl_kind), intent(out), optional :: &
-         sum_squared ! sum of squared residual vector components
-
       ! local variables
 
       integer (kind=int_kind) :: &
@@ -1991,22 +1986,15 @@ subroutine residual_vec (nx_block   , ny_block, &
       character(len=*), parameter :: subname = '(residual_vec)'
 
       !-----------------------------------------------------------------
-      ! compute residual and sum its squared components
+      ! compute residual
       !-----------------------------------------------------------------
 
-      if (present(sum_squared)) then
-         sum_squared = c0
-      endif
-
       do ij = 1, icellu
          i = indxui(ij)
          j = indxuj(ij)
 
          Fx(i,j) = bx(i,j) - Au(i,j)
          Fy(i,j) = by(i,j) - Av(i,j)
-         if (present(sum_squared)) then
-            sum_squared = sum_squared + Fx(i,j)**2 + Fy(i,j)**2
-         endif
       enddo                     ! ij
 
       end subroutine residual_vec
@@ -2470,53 +2458,6 @@ end subroutine formDiag_step2
 
 !=======================================================================
 
-! Compute squared l^2 norm of a grid function (tpu,tpv)
-
-      subroutine calc_L2norm_squared (nx_block, ny_block, &
-                                      icellu  ,           &
-                                      indxui  , indxuj  , &
-                                      tpu     , tpv     , &
-                                      L2norm)
-
-      integer (kind=int_kind), intent(in) :: &
-         nx_block, ny_block, & ! block dimensions
-         icellu                ! total count when iceumask is true
-
-      integer (kind=int_kind), dimension (nx_block*ny_block), intent(in) :: &
-         indxui  , & ! compressed index in i-direction
-         indxuj      ! compressed index in j-direction
-
-      real (kind=dbl_kind), dimension (nx_block,ny_block), intent(in) :: &
-         tpu     , & ! x-component of vector grid function
-         tpv         ! y-component of vector grid function
-
-      real (kind=dbl_kind), intent(out) :: &
-         L2norm      ! squared l^2 norm of vector grid function (tpu,tpv)
-
-      ! local variables
-
-      integer (kind=int_kind) :: &
-         i, j, ij
-
-      character(len=*), parameter :: subname = '(calc_L2norm_squared)'
-
-      !-----------------------------------------------------------------
-      ! compute squared l^2 norm of vector grid function (tpu,tpv)
-      !-----------------------------------------------------------------
-
-      L2norm = c0
-
-      do ij = 1, icellu
-         i = indxui(ij)
-         j = indxuj(ij)
-
-         L2norm = L2norm + tpu(i,j)**2 + tpv(i,j)**2
-      enddo ! ij
-
-      end subroutine calc_L2norm_squared
-
-!=======================================================================
-
 ! Convert a grid function (tpu,tpv) to a one dimensional vector
 
       subroutine arrays_to_vec (nx_block, ny_block  , &