amd-xgbe: Checkpatch fixes

This set of patches resolves some checks reported by the checkpatch
tool.

Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/ethernet/amd/xgbe/xgbe-mdio.c b/drivers/net/ethernet/amd/xgbe/xgbe-mdio.c
index 363b210..7eeb03d 100644
--- a/drivers/net/ethernet/amd/xgbe/xgbe-mdio.c
+++ b/drivers/net/ethernet/amd/xgbe/xgbe-mdio.c
@@ -220,7 +220,7 @@
 	}
 
 	mii = mdiobus_alloc();
-	if (mii == NULL) {
+	if (!mii) {
 		dev_err(pdata->dev, "mdiobus_alloc failed\n");
 		ret = -ENOMEM;
 		goto err_node_get;