mdio_bus: Fix PTR_ERR() usage after initialization to constant

Fix coccinelle warning:

./drivers/net/phy/mdio_bus.c:51:5-12: ERROR: PTR_ERR applied after initialization to constant on line 44
./drivers/net/phy/mdio_bus.c:52:5-12: ERROR: PTR_ERR applied after initialization to constant on line 44

fix this by using IS_ERR before PTR_ERR

Fixes: bafbdd52 ("phylib: Add device reset GPIO support")
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/phy/mdio_bus.c

@@ -48,11 +48,12 @@ static int mdiobus_register_gpiod(struct mdio_device *mdiodev)
 		gpiod = fwnode_get_named_gpiod(&mdiodev->dev.of_node->fwnode,
 					       "reset-gpios", 0, GPIOD_OUT_LOW,
 					       "PHY reset");
-	if (PTR_ERR(gpiod) == -ENOENT ||
-	    PTR_ERR(gpiod) == -ENOSYS)
+	if (IS_ERR(gpiod)) {
+		if (PTR_ERR(gpiod) == -ENOENT || PTR_ERR(gpiod) == -ENOSYS)
 			gpiod = NULL;
-	else if (IS_ERR(gpiod))
+		else
 			return PTR_ERR(gpiod);
+	}
 
 	mdiodev->reset = gpiod;