atomic.h: add atomic64 cmpxchg, xchg and add_unless to x86_64
atomic.h: add atomic64 cmpxchg, xchg and add_unless to x86_64

Signed-off-by: Mathieu Desnoyers <007bef6a47fb57dff675bfa1b0b798b4bdfbfc25@polymtl.ca>
Cc: Andi Kleen <0474aee45985f5ae829f53849df476200e876990@muc.de>
Signed-off-by: Andrew Morton <5c1e68b099950c134891f0b6e179498a8ebe9cf9@linux-foundation.org>
Signed-off-by: Linus Torvalds <69652caca27c8b940640ad396ab71f93cacec34f@linux-foundation.org>

TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas