net: phy: dp83867: Explicitly check against sgmii

dp83867 driver only supports sgmii and not all the newer protocols.
Drop the usage of the generic phy_interface_is_sgmii function and just
matchup to the specific mode supported.

Reported-by: Tom Rini <trini@konsulko.com>
Suggested-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
Suggested-by: Marek BehĂșn <kabel@kernel.org>
Link: https://lore.kernel.org/all/b82ac325-4818-8e72-054b-640268dbf806@mailbox.org/
Signed-off-by: Nishanth Menon <nm@ti.com>
Reviewed-by: Ramon Fried <rfried.dev@gmail.com>
diff --git a/drivers/net/phy/dp83867.c b/drivers/net/phy/dp83867.c
index b861bf7..7111e36 100644
--- a/drivers/net/phy/dp83867.c
+++ b/drivers/net/phy/dp83867.c
@@ -330,7 +330,7 @@
 			      DP83867_RGMIIDCTL, delay);
 	}
 
-	if (phy_interface_is_sgmii(phydev)) {
+	if (phydev->interface == PHY_INTERFACE_MODE_SGMII) {
 		if (dp83867->sgmii_ref_clk_en)
 			phy_write_mmd(phydev, DP83867_DEVADDR, DP83867_SGMIICTL,
 				      DP83867_SGMII_TYPE);