arm: define __smp_xxx

This defines __smp_xxx barriers for arm,
for use by virtualization.

smp_xxx barriers are removed as they are
defined correctly by asm-generic/barriers.h

This reduces the amount of arch-specific boiler-plate code.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>

arch/arm/include/asm/barrier.h

@@ -60,15 +60,9 @@ extern void arm_heavy_mb(void);
 #define dma_wmb()	barrier()
 #endif
 
-#ifndef CONFIG_SMP
-#define smp_mb()	barrier()
-#define smp_rmb()	barrier()
-#define smp_wmb()	barrier()
-#else
-#define smp_mb()	dmb(ish)
-#define smp_rmb()	smp_mb()
-#define smp_wmb()	dmb(ishst)
-#endif
+#define __smp_mb()	dmb(ish)
+#define __smp_rmb()	__smp_mb()
+#define __smp_wmb()	dmb(ishst)
 
 #include <asm-generic/barrier.h>