mdio_bus: Fix PTR_ERR applied after initialization to constant

Fix coccinelle warning:

./drivers/net/phy/mdio_bus.c:67:5-12: ERROR: PTR_ERR applied after initialization to constant on line 62
./drivers/net/phy/mdio_bus.c:68:5-12: ERROR: PTR_ERR applied after initialization to constant on line 62

Fix this by using IS_ERR before PTR_ERR
Reported-by: Hulk Robot <hulkci@huawei.com>
Fixes: 71dd6c0d ("net: phy: add support for reset-controller")
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/phy/mdio_bus.c

@@ -64,11 +64,12 @@ static int mdiobus_register_reset(struct mdio_device *mdiodev)
 	if (mdiodev->dev.of_node)
 		reset = devm_reset_control_get_exclusive(&mdiodev->dev,
 							 "phy");
-	if (PTR_ERR(reset) == -ENOENT ||
-	    PTR_ERR(reset) == -ENOTSUPP)
-		reset = NULL;
-	else if (IS_ERR(reset))
-		return PTR_ERR(reset);
+	if (IS_ERR(reset)) {
+		if (PTR_ERR(reset) == -ENOENT || PTR_ERR(reset) == -ENOSYS)
+			reset = NULL;
+		else
+			return PTR_ERR(reset);
+	}
 
 	mdiodev->reset_ctrl = reset;