ARM: dts: imx6sx: add ARM power domain support

Add ARM power domain in PGC.
Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Reviewed-by: Lucas Stach <l.stach@pengutronix.de>
Acked-by: Dong Aisheng <aisheng.dong@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm/boot/dts/imx6sx.dtsi

@@ -768,6 +768,11 @@ pgc {
 					#address-cells = <1>;
 					#size-cells = <0>;
 
+					power-domain@0 {
+						reg = <0>;
+						#power-domain-cells = <0>;
+					};
+
 					pd_pu: power-domain@1 {
 						reg = <1>;
 						#power-domain-cells = <0>;