xtensa: define __smp_xxx

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

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

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>

arch/xtensa/include/asm/barrier.h

@@ -13,8 +13,8 @@
 #define rmb() barrier()
 #define wmb() mb()
 
-#define smp_mb__before_atomic()		barrier()
-#define smp_mb__after_atomic()		barrier()
+#define __smp_mb__before_atomic()		barrier()
+#define __smp_mb__after_atomic()		barrier()
 
 #include <asm-generic/barrier.h>