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/irda/w83977af_ir.c b/drivers/net/irda/w83977af_ir.c
index f5bb92f..bb8857a 100644
--- a/drivers/net/irda/w83977af_ir.c
+++ b/drivers/net/irda/w83977af_ir.c
@@ -216,22 +216,19 @@
 	/* Allocate memory if needed */
 	self->rx_buff.head =
 		dma_alloc_coherent(NULL, self->rx_buff.truesize,
-				   &self->rx_buff_dma, GFP_KERNEL);
+				   &self->rx_buff_dma, GFP_KERNEL | __GFP_ZERO);
 	if (self->rx_buff.head == NULL) {
 		err = -ENOMEM;
 		goto err_out1;
 	}
 
-	memset(self->rx_buff.head, 0, self->rx_buff.truesize);
-	
 	self->tx_buff.head =
 		dma_alloc_coherent(NULL, self->tx_buff.truesize,
-				   &self->tx_buff_dma, GFP_KERNEL);
+				   &self->tx_buff_dma, GFP_KERNEL | __GFP_ZERO);
 	if (self->tx_buff.head == NULL) {
 		err = -ENOMEM;
 		goto err_out2;
 	}
-	memset(self->tx_buff.head, 0, self->tx_buff.truesize);
 
 	self->rx_buff.in_frame = FALSE;
 	self->rx_buff.state = OUTSIDE_FRAME;