mt7621: fix Linksys E7350 GPIO

When converting this device to use both GMACs, I mistakenly removed
state_default, which prevented GPIO LEDs and keys from being used.

Fixes: f4eef5f2a184 ("ramips: add support for Linksys E7350")

Signed-off-by: Rosen Penev <[email protected]>

target/linux/ramips/dts/mt7621_linksys_e7350.dts

@@ -165,6 +165,13 @@
 	};
 };
 
+&state_default {
+	gpio {
+		groups = "i2c", "uart3", "jtag", "wdt";
+		function = "gpio";
+	};
+};
+
 &gmac1 {
 	status = "okay";
 	label = "wan";