ARM: dts: sun5i: Remove SoC node unit-name to avoid warnings

Our main node for all the in-SoC controllers used to have a unit name. The
unit-name, in addition to being actually false, would not match any reg
property, which generates a warning.

Remove it in order to remove those warnings.

Signed-off-by: Maxime Ripard <[e-mail]>
Acked-by: Chen-Yu Tsai <[e-mail]>

arch/arm/boot/dts/sun5i-a10s.dtsi

···
 		allwinner,pipelines = <&fe0>;
 	};
 
-	soc@1c00000 {
+	soc {
 		hdmi: hdmi@1c16000 {
 			compatible = "allwinner,sun5i-a10s-hdmi";
 			reg = <0x01c16000 0x1000>;

arch/arm/boot/dts/sun5i-a13.dtsi

···
 		allwinner,pipelines = <&fe0>;
 	};
 
-	soc@1c00000 {
+	soc {
 		pwm: pwm@1c20e00 {
 			compatible = "allwinner,sun5i-a13-pwm";
 			reg = <0x01c20e00 0xc>;

arch/arm/boot/dts/sun5i-gr8.dtsi

···
 		allwinner,pipelines = <&fe0>;
 	};
 
-	soc@1c00000 {
+	soc {
 		pwm: pwm@1c20e00 {
 			compatible = "allwinner,sun5i-a10s-pwm";
 			reg = <0x01c20e00 0xc>;

arch/arm/boot/dts/sun5i.dtsi

···
 		};
 	};
 
-	soc@1c00000 {
+	soc {
 		compatible = "simple-bus";
 		#address-cells = <1>;
 		#size-cells = <1>;