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>

drivers/net/ethernet/pasemi/pasemi_mac.c

@@ -441,12 +441,11 @@ static int pasemi_mac_setup_rx_resources(const struct net_device *dev)
 
 	ring->buffers = dma_alloc_coherent(&mac->dma_pdev->dev,
 					   RX_RING_SIZE * sizeof(u64),
-					   &ring->buf_dma, GFP_KERNEL);
+					   &ring->buf_dma,
+					   GFP_KERNEL | __GFP_ZERO);
 	if (!ring->buffers)
 		goto out_ring_desc;
 
-	memset(ring->buffers, 0, RX_RING_SIZE * sizeof(u64));
-
 	write_dma_reg(PAS_DMA_RXCHAN_BASEL(chno),
 		      PAS_DMA_RXCHAN_BASEL_BRBL(ring->chan.ring_dma));