ARM: dts: exynos: replace legacy MMS114 touchscreen x/y properties in GT-N7100

Replace legacy MMS114 touchscreen properties to fix dtschema warnings:

  arch/arm/boot/dts/exynos4412-n710x.dt.yaml: touchscreen@48:
    'x-size', 'y-size' do not match any of the regexes: 'pinctrl-[0-9]+'
  arch/arm/boot/dts/exynos4412-n710x.dt.yaml: touchscreen@48:
    'touchscreen-size-x' is a required property
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Link: https://lore.kernel.org/r/20210505135941.59898-2-krzysztof.kozlowski@canonical.com

arch/arm/boot/dts/exynos4412-n710x.dts

@@ -50,8 +50,8 @@ touchscreen@48 {
 		reg = <0x48>;
 		interrupt-parent = <&gpm2>;
 		interrupts = <3 IRQ_TYPE_EDGE_FALLING>;
-		x-size = <720>;
-		y-size = <1280>;
+		touchscreen-size-x = <720>;
+		touchscreen-size-y = <1280>;
 		avdd-supply = <&ldo23_reg>;
 		vdd-supply = <&ldo24_reg>;
 	};