dts: mt7629: enable JTAG pins by default

The EPHY LEDs belongs to the built-in FE switch of MT7629, which is barely
used. These LED pins on reference boards are used as JTAG socket. So it's
a good idea to change the default state to JTAG, and this will make it
convenience for debugging.

Signed-off-by: Weijie Gao <weijie.gao@mediatek.com>

arch/arm/dts/mt7629-rfb.dts

@@ -36,6 +36,16 @@
 };
 
 &pinctrl {
+	state_default: pinmux_conf {
+		u-boot,dm-pre-reloc;
+
+		mux {
+			function = "jtag";
+			groups = "ephy_leds_jtag";
+			u-boot,dm-pre-reloc;
+		};
+	};
+
 	snfi_pins: snfi-pins {
 		mux {
 			function = "flash";

arch/arm/dts/mt7629.dtsi

@@ -152,6 +152,12 @@
 		compatible = "mediatek,mt7629-pinctrl";
 		reg = <0x10217000 0x8000>;
 
+		pinctrl-names = "default";
+		pinctrl-0 = <&state_default>;
+
+		state_default: pinmux_conf {
+		};
+
 		gpio: gpio-controller {
 			gpio-controller;
 			#gpio-cells = <2>;