drm/amd/powerplay: implement sysfs of pp_table for smu11 (v2)

add pp_table sysfs interface for new sw-smu.
get: return pptable raw data
set: write pptable raw data to pptable, then reset smu (hw_fini -> hw_init)

v2: fix mutex lock issue

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>