remoteproc: imx_rproc: Support kicking Mcore from Linux for i.MX8QXP

When M4 is in the same hardware partition with Cortex-A, it
could be start/stop by Linux.

Added power domain to make sure M4 could run, it requires several power
domains to work. Make clock always optional for i.MX8QXP, because
SCFW handles it when power up M4 core.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
Link: https://lore.kernel.org/r/20221021041526.3696483-5-peng.fan@oss.nxp.com
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>