arm: dts: mt7623: remove unused compatible string for pio node

MT7623 has its own compatible in pinctrl driver so we don't need the
backward compatible for it.
Signed-off-by: NRyder Lee <ryder.lee@mediatek.com>
Signed-off-by: NMatthias Brugger <matthias.bgg@gmail.com>

arch/arm/boot/dts/mt7623.dtsi

@@ -227,8 +227,7 @@ pericfg: syscon@10003000 {
 	};
 
 	pio: pinctrl@10005000 {
-		compatible = "mediatek,mt7623-pinctrl",
-			     "mediatek,mt2701-pinctrl";
+		compatible = "mediatek,mt7623-pinctrl";
 		reg = <0 0x1000b000 0 0x1000>;
 		mediatek,pctl-regmap = <&syscfg_pctl_a>;
 		pins-are-numbered;