arm64: dts: imx8mm: remove otg1/2 power domain dependency on hsio

pgc_otg1/2 are independent power domain of hsio, they for usb phy,
so remove hsio power domain dependency from its node.

Fixes: d39d4bb1 ("arm64: dts: imx8mm: add GPC node")
Signed-off-by: Li Jun <jun.li@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm64/boot/dts/freescale/imx8mm.dtsi

@@ -674,13 +674,11 @@ pgc_pcie: power-domain@1 {
 					pgc_otg1: power-domain@2 {
 						#power-domain-cells = <0>;
 						reg = <IMX8MM_POWER_DOMAIN_OTG1>;
-						power-domains = <&pgc_hsiomix>;
 					};
 
 					pgc_otg2: power-domain@3 {
 						#power-domain-cells = <0>;
 						reg = <IMX8MM_POWER_DOMAIN_OTG2>;
-						power-domains = <&pgc_hsiomix>;
 					};
 
 					pgc_gpumix: power-domain@4 {