net: broadcom: bcm4908_enet: drop unneeded memset()

dma_alloc_coherent takes care of zeroing allocated memory
Suggested-by: NAndrew Lunn <andrew@lunn.ch>
Signed-off-by: NRafał Miłecki <rafal@milecki.pl>
Reviewed-by: NAndrew Lunn <andrew@lunn.ch>
Reviewed-by: NFlorian Fainelli <f.fainelli@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/broadcom/bcm4908_enet.c

@@ -163,8 +163,6 @@ static int bcm4908_dma_alloc_buf_descs(struct bcm4908_enet *enet,
 	if (!ring->slots)
 		goto err_free_buf_descs;
 
-	memset(ring->cpu_addr, 0, size);
-
 	ring->read_idx = 0;
 	ring->write_idx = 0;