[patch] powerpc: smp_wmb lwsync optimisation fix

[Nick Piggin]

A previous change removed __SUBARCH_HAS_LWSYNC define, and replaced it
with __powerpc64__. smp_wmb() seems to be the last place not updated.

Signed-off-by: Nick Piggin <npiggin at suse.de>
---
Index: linux-2.6/arch/powerpc/include/asm/system.h
===================================================================
--- linux-2.6.orig/arch/powerpc/include/asm/system.h	2008-11-01 20:31:51.000000000 +1100
+++ linux-2.6/arch/powerpc/include/asm/system.h	2008-11-01 20:32:33.000000000 +1100
@@ -44,7 +44,7 @@
 #define AT_VECTOR_SIZE_ARCH 6 /* entries in ARCH_DLINFO */
 #ifdef CONFIG_SMP
 
-#ifdef __SUBARCH_HAS_LWSYNC
+#if defined(__powerpc64__)
 #    define SMPWMB      lwsync
 #else
 #    define SMPWMB      eieio