x86, asm: Use CC_SET()/CC_OUT() in <asm/percpu.h>

Remove open-coded uses of set instructions to use CC_SET()/CC_OUT() in
<asm/percpu.h>.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Link: http://lkml.kernel.org/r/1465414726-197858-8-git-send-email-hpa@linux.intel.com


Reviewed-by: Andy Lutomirski <luto@kernel.org>
Reviewed-by: Borislav Petkov <bp@suse.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>