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/faraday/ftgmac100.c b/drivers/net/ethernet/faraday/ftgmac100.c
index 7c361d1..0e817e6 100644
--- a/drivers/net/ethernet/faraday/ftgmac100.c
+++ b/drivers/net/ethernet/faraday/ftgmac100.c
@@ -780,12 +780,11 @@
 
 	priv->descs = dma_alloc_coherent(priv->dev,
 					 sizeof(struct ftgmac100_descs),
-					 &priv->descs_dma_addr, GFP_KERNEL);
+					 &priv->descs_dma_addr,
+					 GFP_KERNEL | __GFP_ZERO);
 	if (!priv->descs)
 		return -ENOMEM;
 
-	memset(priv->descs, 0, sizeof(struct ftgmac100_descs));
-
 	/* initialize RX ring */
 	ftgmac100_rxdes_set_end_of_ring(&priv->descs->rxdes[RX_QUEUE_ENTRIES - 1]);