powerpc: Rename LWSYNC_ON_SMP to PPC_RELEASE_BARRIER, ISYNC_ON_SMP to PPC_ACQUIRE_BARRIER

For performance reasons we are about to change ISYNC_ON_SMP to sometimes be
lwsync. Now that the macro name doesn't make sense, change it and LWSYNC_ON_SMP
to better explain what the barriers are doing.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/arch/powerpc/include/asm/synch.h b/arch/powerpc/include/asm/synch.h
index 28f6ddb..5db1f0d 100644
--- a/arch/powerpc/include/asm/synch.h
+++ b/arch/powerpc/include/asm/synch.h
@@ -37,11 +37,11 @@
 #endif
 
 #ifdef CONFIG_SMP
-#define ISYNC_ON_SMP	"\n\tisync\n"
-#define LWSYNC_ON_SMP	stringify_in_c(LWSYNC) "\n"
+#define PPC_ACQUIRE_BARRIER	"\n\tisync\n"
+#define PPC_RELEASE_BARRIER	stringify_in_c(LWSYNC) "\n"
 #else
-#define ISYNC_ON_SMP
-#define LWSYNC_ON_SMP
+#define PPC_ACQUIRE_BARRIER
+#define PPC_RELEASE_BARRIER
 #endif
 
 #endif /* __KERNEL__ */