ramips: further DTS improvements for Edimax RG21S

This fixes the state_default node by setting the correct groups and
inheriting &state_default from parent DTSI directly.

The compatible for the wifi nodes is changed to the more generic
mediatek,mt76.

Signed-off-by: Adrian Schmutzler <freifunk@adrianschmutzler.de>

target/linux/ramips/dts/mt7621_edimax_rg21s.dts

@@ -109,7 +109,7 @@
 
 &pcie0 {
 	wifi0: wifi@0,0 {
-		compatible = "pci14c3,7615";
+		compatible = "mediatek,mt76";
 		reg = <0x0000 0 0 0 0>;
 		mediatek,mtd-eeprom = <&factory 0x0000>;
 		ieee80211-freq-limit = <2400000 2500000>;
@@ -118,7 +118,7 @@
 
 &pcie1 {
 	wifi1: wifi@0,0 {
-		compatible = "pci14c3,7615";
+		compatible = "mediatek,mt76";
 		reg = <0x0000 0 0 0 0>;
 		mediatek,mtd-eeprom = <&factory 0x8000>;
 		ieee80211-freq-limit = <5000000 6000000>;
@@ -134,12 +134,10 @@
 	};
 };
 
-&pinctrl {
-	state_default: pinctrl0 {
-		gpio {
-			ralink,group = "wdt", "rgmii2", "jtag", "mdio";
-			ralink,function = "gpio";
-		};
+&state_default {
+	gpio {
+		ralink,group = "uart3", "uart2", "jtag", "wdt";
+		ralink,function = "gpio";
 	};
 };