drivers:net: dma_alloc_coherent: use __GFP_ZERO instead of memset(, 0)

Reduce the number of calls required to alloc
a zeroed block of memory.

Trivially reduces overall object size.

Other changes around these removals
o Neaten call argument alignment
o Remove an unnecessary OOM message after dma_alloc_coherent failure
o Remove unnecessary gfp_t stack variable

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/ethernet/aeroflex/greth.c b/drivers/net/ethernet/aeroflex/greth.c
index 3a9fbac..2692954 100644
--- a/drivers/net/ethernet/aeroflex/greth.c
+++ b/drivers/net/ethernet/aeroflex/greth.c
@@ -1466,25 +1466,21 @@
 	/* Allocate TX descriptor ring in coherent memory */
 	greth->tx_bd_base = dma_alloc_coherent(greth->dev, 1024,
 					       &greth->tx_bd_base_phys,
-					       GFP_KERNEL);
+					       GFP_KERNEL | __GFP_ZERO);
 	if (!greth->tx_bd_base) {
 		err = -ENOMEM;
 		goto error3;
 	}
 
-	memset(greth->tx_bd_base, 0, 1024);
-
 	/* Allocate RX descriptor ring in coherent memory */
 	greth->rx_bd_base = dma_alloc_coherent(greth->dev, 1024,
 					       &greth->rx_bd_base_phys,
-					       GFP_KERNEL);
+					       GFP_KERNEL | __GFP_ZERO);
 	if (!greth->rx_bd_base) {
 		err = -ENOMEM;
 		goto error4;
 	}
 
-	memset(greth->rx_bd_base, 0, 1024);
-
 	/* Get MAC address from: module param, OF property or ID prom */
 	for (i = 0; i < 6; i++) {
 		if (macaddr[i] != 0)