drm/amd/powerplay: add power consumption display support in debugfs

The additional output are:
vddc power in Watt;
vddci power in Watt;
max gpu power in Watt;
average gpu power in Watt.

Signed-off-by: Eric Huang <JinHuiEric.Huang@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>