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/wireless/b43legacy/dma.c b/drivers/net/wireless/b43legacy/dma.c
index 07d7e92..faeafe2 100644
--- a/drivers/net/wireless/b43legacy/dma.c
+++ b/drivers/net/wireless/b43legacy/dma.c
@@ -334,10 +334,9 @@
 	ring->descbase = dma_alloc_coherent(ring->dev->dev->dma_dev,
 					    B43legacy_DMA_RINGMEMSIZE,
 					    &(ring->dmabase),
-					    GFP_KERNEL);
+					    GFP_KERNEL | __GFP_ZERO);
 	if (!ring->descbase)
 		return -ENOMEM;
-	memset(ring->descbase, 0, B43legacy_DMA_RINGMEMSIZE);
 
 	return 0;
 }