imx: power-domain: Add i.MX8MP HSIOMIX driver

imx: power-domain: Add i.MX8MP HSIOMIX driver

Add trivial driver for i.MX8MP HSIOMIX handling. This is responsible
for enabling the GPCv2 power domains and clock for USB 3.0 and PCIe
in the correct order. Currently supported is the USB 3.0 part which
can be tested, PCIe support should be easy to add.

Tested-By: Tim Harvey <tharvey@gateworks.com> #imx8mp-venice-gw74xx
Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Fabio Estevam <festevam@gmail.com>
Cc: Peng Fan <peng.fan@nxp.com>
Cc: Stefano Babic <sbabic@denx.de>