staging: mt7621-eth: fix compile warning.

This code generates a waring as PHY_GBIT_FEATURES is "long" but
->supported in "int".

It looks likely that "PHY_1000BT_FEATURES" is the correct define to
use - it is intended to be used with the ->features field.
Signed-off-by: NeilBrown <neil@brown.name>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/mt7621-eth/mdio.c

@@ -89,7 +89,7 @@ int mtk_connect_phy_node(struct mtk_eth *eth, struct mtk_mac *mac,
 		return -ENODEV;
 	}
 
-	phydev->supported &= PHY_GBIT_FEATURES;
+	phydev->supported &= PHY_1000BT_FEATURES;
 	phydev->advertising = phydev->supported;
 
 	dev_info(eth->dev,