net: phy: Utilize phy_interface_is_rgmii

Update all open-coded tests for all 4 PHY_INTERFACE_MODE_RGMII* values
to use the newly introduced helper: phy_interface_is_rgmii.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/phy/marvell.c b/drivers/net/phy/marvell.c
index 1b1698f..f721444 100644
--- a/drivers/net/phy/marvell.c
+++ b/drivers/net/phy/marvell.c
@@ -317,10 +317,7 @@
 	if (err < 0)
 		return err;
 
-	if ((phydev->interface == PHY_INTERFACE_MODE_RGMII) ||
-	    (phydev->interface == PHY_INTERFACE_MODE_RGMII_ID) ||
-	    (phydev->interface == PHY_INTERFACE_MODE_RGMII_RXID) ||
-	    (phydev->interface == PHY_INTERFACE_MODE_RGMII_TXID)) {
+	if (phy_interface_is_rgmii(phydev)) {
 
 		mscr = phy_read(phydev, MII_88E1121_PHY_MSCR_REG) &
 			MII_88E1121_PHY_MSCR_DELAY_MASK;
@@ -469,10 +466,7 @@
 	int err;
 	int temp;
 
-	if ((phydev->interface == PHY_INTERFACE_MODE_RGMII) ||
-	    (phydev->interface == PHY_INTERFACE_MODE_RGMII_ID) ||
-	    (phydev->interface == PHY_INTERFACE_MODE_RGMII_RXID) ||
-	    (phydev->interface == PHY_INTERFACE_MODE_RGMII_TXID)) {
+	if (phy_interface_is_rgmii(phydev)) {
 
 		temp = phy_read(phydev, MII_M1111_PHY_EXT_CR);
 		if (temp < 0)