ixgb: use dma_zalloc_coherent instead of allocator/memset

Use dma_zalloc_coherent instead of dma_alloc_coherent
followed by memset 0.
Signed-off-by: NYueHaibing <yuehaibing@huawei.com>
Tested-by: NAndrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/ixgb/ixgb_main.c

@@ -771,14 +771,13 @@ ixgb_setup_rx_resources(struct ixgb_adapter *adapter)
 	rxdr->size = rxdr->count * sizeof(struct ixgb_rx_desc);
 	rxdr->size = ALIGN(rxdr->size, 4096);
 
-	rxdr->desc = dma_alloc_coherent(&pdev->dev, rxdr->size, &rxdr->dma,
+	rxdr->desc = dma_zalloc_coherent(&pdev->dev, rxdr->size, &rxdr->dma,
 					 GFP_KERNEL);
 
 	if (!rxdr->desc) {
 		vfree(rxdr->buffer_info);
 		return -ENOMEM;
 	}
-	memset(rxdr->desc, 0, rxdr->size);
 
 	rxdr->next_to_clean = 0;
 	rxdr->next_to_use = 0;