config: always-arch: don't subst TARGET_CPU

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ahelenia Ziemiańska <nabijaczleweli@nabijaczleweli.xyz>
Closes openzfs#13225

config/always-arch.m4

@@ -2,10 +2,6 @@ dnl #
 dnl # Set the target cpu architecture.  This allows the
 dnl # following syntax to be used in a Makefile.am.
 dnl #
-dnl # ifeq ($(TARGET_CPU),x86_64)
-dnl # ...
-dnl # endif
-dnl #
 dnl # if TARGET_CPU_POWERPC
 dnl # ...
 dnl # else
@@ -34,8 +30,6 @@ AC_DEFUN([ZFS_AC_CONFIG_ALWAYS_ARCH], [
 		;;
 	esac
 
-	AC_SUBST(TARGET_CPU)
-
 	AM_CONDITIONAL([TARGET_CPU_X86_64], test $TARGET_CPU = x86_64)
 	AM_CONDITIONAL([TARGET_CPU_POWERPC], test $TARGET_CPU = powerpc)
 ])