x86, asm: change GEN_*_RMWcc() to use CC_SET()/CC_OUT()

Change the GEN_*_RMWcc() macros to use the CC_SET()/CC_OUT() macros
defined in <asm/asm.h>, and disable the use of asm goto if
__GCC_ASM_FLAG_OUTPUTS__ is enabled.  This allows gcc to receive the
flags output directly in gcc 6+.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Link: http://lkml.kernel.org/r/1465414726-197858-6-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>