arm64: dts: imx8mm: correct usb power domains

pgc_otg1/2 is actual the power domain of usb PHY, usb controller
is in hsio power domain, and pgc_otg1/2 is required to be powered
up to detect usb remote wakeup, so move the pgc_otg1/2 power domain
to the usb phy node.

Fixes: 01df28d8 ("arm64: dts: imx8mm: put USB controllers into power-domains")
Signed-off-by: Li Jun <jun.li@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>