net: phy: ti: Fix dp83867 RGMII_TXID interface path

There is code that is specifically for RGMII_TXID interface, but this
will never get used because the code checks that the RGMII interface
is RGMII_ID to RGMII_RXID; RGMII_TXID is after this.

To fix this and avoid similar problems in the future, use the
phy_interface_is_rgmii helper function.

Signed-off-by: Phil Edworthy <phil.edworthy@renesas.com>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>
diff --git a/drivers/net/phy/ti.c b/drivers/net/phy/ti.c
index c55dd97..5e2b2dd 100644
--- a/drivers/net/phy/ti.c
+++ b/drivers/net/phy/ti.c
@@ -246,8 +246,7 @@
 		phy_write(phydev, MDIO_DEVAD_NONE, MII_DP83867_BISCR, 0x0);
 	}
 
-	if ((phydev->interface >= PHY_INTERFACE_MODE_RGMII_ID) &&
-	    (phydev->interface <= PHY_INTERFACE_MODE_RGMII_RXID)) {
+	if (phy_interface_is_rgmii(phydev)) {
 		val = phy_read_mmd_indirect(phydev, DP83867_RGMIICTL,
 					    DP83867_DEVADDR, phydev->addr);