drm/amd/powerplay: add pp_tables_get_response_times function in process pptables

The pp_tables_get_response_times function will be used on iceland HW
mananger.

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