drm/amd/powerplay: no pptable transfer and dpms enabled with "dpm=0"

Honor the 'dpm' module parameter setting on SW SMU routine as what
we did on previous ASICs. SMU FW loading is still proceeded even
with "dpm=0".

Signed-off-by: Evan Quan <evan.quan@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>