thermal: rcar: add pm_runtime_xxx() support

Current rcar_thermal() didn't care about own power.
Without this patch, rcar_thermal doesn't work on APE6 board

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Zhang Rui <rui.zhang@intel.com>