clk: imx95-blk-ctl: Save/restore registers when RPM routines are called

clk: imx95-blk-ctl: Save/restore registers when RPM routines are called

When runtime PM is used for clock providers that are part of a power
domain, the power domain supply is cut off during runtime suspend. This
causes all BLK CTL registers belonging to that power domain to reset. To
prevent this, save the state of the registers before entering suspend
and restore them on resume. Additionally, disable the APB clock during
suspend to minimize power consumption.

Signed-off-by: Laurentiu Palcu <laurentiu.palcu@oss.nxp.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Link: https://lore.kernel.org/r/20250804131450.3918846-3-laurentiu.palcu@oss.nxp.com
Signed-off-by: Abel Vesa <abel.vesa@linaro.org>