mediatek: mt7988: move gpio-controller up and rename pinctrl to pio

Move gpio-controller up to pinctrl node and rename label to "pio" to
match the label used in upstream kernel linux.

Update any DTS that reference the pinctrl to follow the new naming and
structure.

Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
diff --git a/arch/arm/dts/mt7988-sd-rfb.dts b/arch/arm/dts/mt7988-sd-rfb.dts
index 38727a2..63e9231 100644
--- a/arch/arm/dts/mt7988-sd-rfb.dts
+++ b/arch/arm/dts/mt7988-sd-rfb.dts
@@ -53,7 +53,7 @@
 	};
 };
 
-&pinctrl {
+&pio {
 	i2c1_pins: i2c1-pins {
 		mux {
 			function = "i2c";