firmware: imx: scu-pd: ignore power domain not owned

Should not register power domain that not owned by current
partition.

Alought power domains will not be registered when power on failure,
we have to let CPU waste more cycles.

Whether power on or owned check, both need communicate with SCU,
but with owned check, we no need to run more code path to save CPU
cycles.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
Reviewed-by: Leonard Crestez <leonard.crestez@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>