net: phy: xilinx: Drop #ifdef CONFIG_DM_ETH around phy_connect_gmii2rgmii()

At present phy_connect_gmii2rgmii() is implemented using a DM API
dev_of_offset() hence it cannot support a non-DM configuration.
Remove the non-DM version prototype of phy_connect_gmii2rgmii()
and make the driver depend on CONFIG_DM_ETH.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Acked-by: Michal Simek <michal.simek@xilinx.com>
Reviewed-by: Ramon Fried <rfried.dev@gmail.com>
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Priyanka Jain <priyanka.jain@nxp.com>
diff --git a/drivers/net/phy/Kconfig b/drivers/net/phy/Kconfig
index d695030..070ffa8 100644
--- a/drivers/net/phy/Kconfig
+++ b/drivers/net/phy/Kconfig
@@ -292,6 +292,7 @@
 
 config PHY_XILINX_GMII2RGMII
 	bool "Xilinx GMII to RGMII Ethernet PHYs support"
+	depends on DM_ETH
 	help
 	  This adds support for Xilinx GMII to RGMII IP core. This IP acts
 	  as bridge between MAC connected over GMII and external phy that
diff --git a/drivers/net/phy/phy.c b/drivers/net/phy/phy.c
index d464379..c7cdf64 100644
--- a/drivers/net/phy/phy.c
+++ b/drivers/net/phy/phy.c
@@ -942,15 +942,9 @@
 }
 
 #ifdef CONFIG_PHY_XILINX_GMII2RGMII
-#ifdef CONFIG_DM_ETH
 static struct phy_device *phy_connect_gmii2rgmii(struct mii_dev *bus,
 						 struct udevice *dev,
 						 phy_interface_t interface)
-#else
-static struct phy_device *phy_connect_gmii2rgmii(struct mii_dev *bus,
-						 struct eth_device *dev,
-						 phy_interface_t interface)
-#endif
 {
 	struct phy_device *phydev = NULL;
 	ofnode node = dev_ofnode(dev);