phy: core: clean up unused ethernet specific phy modes

After recent changes PHY_MODE_SGMII, PHY_MODE_2500SGMII, PHY_MODE_QSGMII,
PHY_MODE_10GKR are not used any more and can be removed. Hence - remove
them.
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>

include/linux/phy/phy.h

@@ -35,10 +35,6 @@ enum phy_mode {
 	PHY_MODE_USB_DEVICE_HS,
 	PHY_MODE_USB_DEVICE_SS,
 	PHY_MODE_USB_OTG,
-	PHY_MODE_SGMII,
-	PHY_MODE_2500SGMII,
-	PHY_MODE_QSGMII,
-	PHY_MODE_10GKR,
 	PHY_MODE_UFS_HS_A,
 	PHY_MODE_UFS_HS_B,
 	PHY_MODE_PCIE,