ibmvnic: remove unnecessary rmb() inside ibmvnic_poll

rmb() can be removed since:
1. pending_scrq() has dma_rmb() at the function end;
2. dma_rmb(), though weaker, is enough here.

Signed-off-by: Lijun Pan <ljp@linux.ibm.com>
Acked-by: Dwip Banerjee <dnbanerg@us.ibm.com>
Acked-by: Thomas Falcon <tlfalcon@linux.ibm.com>
Reviewed-by: Brian King <brking@linux.vnet.ibm.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/ibm/ibmvnic.c

@@ -2510,7 +2510,6 @@ restart_poll:
 		if (napi_complete_done(napi, frames_processed)) {
 			enable_scrq_irq(adapter, rx_scrq);
 			if (pending_scrq(adapter, rx_scrq)) {
-				rmb();
 				if (napi_reschedule(napi)) {
 					disable_scrq_irq(adapter, rx_scrq);
 					goto restart_poll;