drm/amd/display: Add Freesync Panel DM code

We need certain conditions for replay to be enabled, so create an
interface in DM to enable/disable replay.

Signed-off-by: Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>