Fix build error on freebsd

Fixes:

checking for config freebsd12.1... no
checking for config freebsd... found
compiler '/home/svcpetsc/petsc-hash-pkgs/39f577/bin/mpicc' is GNU gcc-9.2.0
compiler '/home/svcpetsc/petsc-hash-pkgs/39f577/bin/mpif90' is GNU gfortran-9.2.0.: cannot open ./config/classic-fflags: No such file or directory

config/freebsd

@@ -67,9 +67,6 @@ fi
 # Figure out Intel oneAPI FC compiler flags
 . $srcdir/config/oneapi-fflags
 
-# Figure out Intel classic FC compiler flags
-. $srcdir/config/classic-fflags
-
 # The default C++ compiler
 
 # The default compiler is 'c++'.