soc: imx: gpcv2: add support for i.MX8MN power domains

This adds support for the power domains founds on i.MX8MN. The Nano
has fewer domains than the Mini, and the access to some of these domains
is different than that of the Mini, the Mini power domains cannot be
reused.

Signed-off-by: Adam Ford <aford173@gmail.com>
Acked-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>