Lose constraints on cmpxchg

From: Jan Beulich <jbeulich@novell.com>

While only cosmetic for x86-64, this adjusts the cmpxchg code appearantly
inherited from i386 to use more generic constraints.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Andi Kleen <ak@suse.de>

Index: linux/include/asm-x86_64/system.h
===================================================================
--- linux.orig/include/asm-x86_64/system.h
+++ linux/include/asm-x86_64/system.h
@@ -247,25 +247,25 @@ static inline unsigned long __cmpxchg(vo
 	case 1:
 		__asm__ __volatile__(LOCK_PREFIX "cmpxchgb %b1,%2"
 				     : "=a"(prev)
-				     : "q"(new), "m"(*__xg(ptr)), "0"(old)
+				     : "r"(new), "m"(*__xg(ptr)), "0"(old)
 				     : "memory");
 		return prev;
 	case 2:
 		__asm__ __volatile__(LOCK_PREFIX "cmpxchgw %w1,%2"
 				     : "=a"(prev)
-				     : "q"(new), "m"(*__xg(ptr)), "0"(old)
+				     : "r"(new), "m"(*__xg(ptr)), "0"(old)
 				     : "memory");
 		return prev;
 	case 4:
 		__asm__ __volatile__(LOCK_PREFIX "cmpxchgl %k1,%2"
 				     : "=a"(prev)
-				     : "q"(new), "m"(*__xg(ptr)), "0"(old)
+				     : "r"(new), "m"(*__xg(ptr)), "0"(old)
 				     : "memory");
 		return prev;
 	case 8:
 		__asm__ __volatile__(LOCK_PREFIX "cmpxchgq %1,%2"
 				     : "=a"(prev)
-				     : "q"(new), "m"(*__xg(ptr)), "0"(old)
+				     : "r"(new), "m"(*__xg(ptr)), "0"(old)
 				     : "memory");
 		return prev;
 	}