arch/powerpc/fsl_rmu: Use dma_zalloc_coherent

Replaced dma_alloc_coherent + memset with dma_zalloc_coherent
Signed-off-by: Sabyasachi Gupta <sabyasachi.linux@gmail.com>
Signed-off-by: Scott Wood <oss@buserror.net>

arch/powerpc/sysdev/fsl_rmu.c

@@ -756,15 +756,13 @@ fsl_open_outb_mbox(struct rio_mport *mport, void *dev_id, int mbox, int entries)
 	}
 
 	/* Initialize outbound message descriptor ring */
-	rmu->msg_tx_ring.virt = dma_alloc_coherent(priv->dev,
+	rmu->msg_tx_ring.virt = dma_zalloc_coherent(priv->dev,
 				rmu->msg_tx_ring.size * RIO_MSG_DESC_SIZE,
 				&rmu->msg_tx_ring.phys, GFP_KERNEL);
 	if (!rmu->msg_tx_ring.virt) {
 		rc = -ENOMEM;
 		goto out_dma;
 	}
-	memset(rmu->msg_tx_ring.virt, 0,
-			rmu->msg_tx_ring.size * RIO_MSG_DESC_SIZE);
 	rmu->msg_tx_ring.tx_slot = 0;
 
 	/* Point dequeue/enqueue pointers at first entry in ring */