dm: sunxi: Support driver model for Ethernet

Adjust the Ethernet initialisation code to support driver model.
It is no-longer necessary to call designware_initialize(). The device will
be probed when it is used. The PHY type and GMAC base will come from the
device tree.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/board/sunxi/gmac.c b/board/sunxi/gmac.c
index 63a7360..d90eed4 100644
--- a/board/sunxi/gmac.c
+++ b/board/sunxi/gmac.c
@@ -80,11 +80,15 @@
 		sunxi_gpio_set_cfgpin(pin, SUN6I_GPA_GMAC);
 #endif
 
-#ifdef CONFIG_RGMII
-	return designware_initialize(SUNXI_GMAC_BASE, PHY_INTERFACE_MODE_RGMII);
-#elif defined CONFIG_GMII
-	return designware_initialize(SUNXI_GMAC_BASE, PHY_INTERFACE_MODE_GMII);
+#ifdef CONFIG_DM_ETH
+	return 0;
 #else
+# ifdef CONFIG_RGMII
+	return designware_initialize(SUNXI_GMAC_BASE, PHY_INTERFACE_MODE_RGMII);
+# elif defined CONFIG_GMII
+	return designware_initialize(SUNXI_GMAC_BASE, PHY_INTERFACE_MODE_GMII);
+# else
 	return designware_initialize(SUNXI_GMAC_BASE, PHY_INTERFACE_MODE_MII);
+# endif
 #endif
 }