drivers:net: Convert dma_alloc_coherent(...__GFP_ZERO) to dma_zalloc_coherent

__GFP_ZERO is an uncommon flag and perhaps is better
not used.  static inline dma_zalloc_coherent exists
so convert the uses of dma_alloc_coherent with __GFP_ZERO
to the more common kernel style with zalloc.

Remove memset from the static inline dma_zalloc_coherent
and add just one use of __GFP_ZERO instead.

Trivially reduces the size of the existing uses of
dma_zalloc_coherent.

Realign arguments as appropriate.

Signed-off-by: Joe Perches <joe@perches.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Acked-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Acked-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/ethernet/aeroflex/greth.c b/drivers/net/ethernet/aeroflex/greth.c
index 7ff4b30..e066945 100644
--- a/drivers/net/ethernet/aeroflex/greth.c
+++ b/drivers/net/ethernet/aeroflex/greth.c
@@ -1464,18 +1464,18 @@
 	}
 
 	/* Allocate TX descriptor ring in coherent memory */
-	greth->tx_bd_base = dma_alloc_coherent(greth->dev, 1024,
-					       &greth->tx_bd_base_phys,
-					       GFP_KERNEL | __GFP_ZERO);
+	greth->tx_bd_base = dma_zalloc_coherent(greth->dev, 1024,
+						&greth->tx_bd_base_phys,
+						GFP_KERNEL);
 	if (!greth->tx_bd_base) {
 		err = -ENOMEM;
 		goto error3;
 	}
 
 	/* Allocate RX descriptor ring in coherent memory */
-	greth->rx_bd_base = dma_alloc_coherent(greth->dev, 1024,
-					       &greth->rx_bd_base_phys,
-					       GFP_KERNEL | __GFP_ZERO);
+	greth->rx_bd_base = dma_zalloc_coherent(greth->dev, 1024,
+						&greth->rx_bd_base_phys,
+						GFP_KERNEL);
 	if (!greth->rx_bd_base) {
 		err = -ENOMEM;
 		goto error4;