drm/amd/powerplay: add interface to populate smc pptable (v2)

This patch adds interface to populate smc pptable for smu.
It's to set initialized values (get from vbios) to dpm tables context such as
gfxclk, memclk, dcefclk, and etc. And enable the DPM feature for each type of
clks.

v2: add detailed info to describe this function

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