Staging: hv: vmbus: Fix a memory barrier call in vmbus_drv.c

Use the correct memory barrier call in vmbus_drv.c
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NHaiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: NAbhishek Kane <v-abkane@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

drivers/staging/hv/vmbus_drv.c

@@ -455,7 +455,7 @@ static void vmbus_on_msg_dpc(unsigned long data)
 		 * will not deliver any more messages since there is
 		 * no empty slot
 		 */
-		mb();
+		smp_mb();
 
 		if (msg->header.message_flags.msg_pending) {
 			/*