x86, percpu: Use ASM_NOP4 instead of hardcoding P6_NOP4

For use in assembly constants, use the ASM_NOP* defines.
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Tejun Heo <tj@kernel.org>
Link: http://lkml.kernel.org/r/1303166160-10315-2-git-send-email-hpa@linux.intel.com

arch/x86/include/asm/percpu.h

@@ -517,7 +517,7 @@ do {									\
 	typeof(o2) __o2 = o2;						\
 	typeof(o2) __n2 = n2;						\
 	typeof(o2) __dummy;						\
-	alternative_io("call this_cpu_cmpxchg16b_emu\n\t" P6_NOP4,	\
+	alternative_io("call this_cpu_cmpxchg16b_emu\n\t" ASM_NOP4,	\
 		       "cmpxchg16b " __percpu_prefix "(%%rsi)\n\tsetz %0\n\t",	\
 		       X86_FEATURE_CX16,				\
 		       ASM_OUTPUT2("=a"(__ret), "=d"(__dummy)),		\