drm/radeon/kms: DCE3/4 AdjustPixelPll updates

Add options necessary bits for:
- SS on DP
- SS on LVDS
- set clocks right for DP
- deep color on hdmi (needs additional encoder and edid work as well)

Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>