x86: Remove duplication of 16-bit CFLAGS

Define them once in arch/x86/Makefile instead of twice.

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Link: http://lkml.kernel.org/r/1389180083-23249-1-git-send-email-David.Woodhouse@intel.com


Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>