drivers: net: cpsw: init phy with gigabit features

CPSW ia a gigabit device. Use the PHY_GBIT_FEATURES macro to determine phy
supported features.
Tested on cm_t335.

Signed-off-by: Ilya Ledvich <ilya@compulab.co.il>
diff --git a/drivers/net/cpsw.c b/drivers/net/cpsw.c
index dd6c26a..bd5fba2 100644
--- a/drivers/net/cpsw.c
+++ b/drivers/net/cpsw.c
@@ -941,11 +941,7 @@
 {
 	struct cpsw_priv *priv = (struct cpsw_priv *)dev->priv;
 	struct phy_device *phydev;
-	u32 supported = (SUPPORTED_10baseT_Half |
-			SUPPORTED_10baseT_Full |
-			SUPPORTED_100baseT_Half |
-			SUPPORTED_100baseT_Full |
-			SUPPORTED_1000baseT_Full);
+	u32 supported = PHY_GBIT_FEATURES;
 
 	phydev = phy_connect(priv->bus,
 			slave->data->phy_addr,