drm/amd/powerplay: implement smu_init[fini]_power function for smu11

This patch implements smu_init[fini]_power function for smu v11.

Signed-off-by: Kevin Wang <Kevin1.Wang@amd.com>
Reviewed-by: Huang Rui <ray.huang@amd.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>