vector and core register push/restore code are duplicated.

this patch unify them as one copy.

*no functional change*

ok to install?

thanks.

gcc/
   * config/aarch64/aarch64.c (aarch64_save_or_restore_fprs): Deleted.
   (aarch64_save_callee_saves): New function to handle reg save
   for both core and vectore regs.