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/sfc/nic.c b/drivers/net/ethernet/sfc/nic.c
index f9f5df8..7b87798 100644
--- a/drivers/net/ethernet/sfc/nic.c
+++ b/drivers/net/ethernet/sfc/nic.c
@@ -305,11 +305,11 @@
 			 unsigned int len)
 {
 	buffer->addr = dma_alloc_coherent(&efx->pci_dev->dev, len,
-					  &buffer->dma_addr, GFP_ATOMIC);
+					  &buffer->dma_addr,
+					  GFP_ATOMIC | __GFP_ZERO);
 	if (!buffer->addr)
 		return -ENOMEM;
 	buffer->len = len;
-	memset(buffer->addr, 0, len);
 	return 0;
 }