Reapply "Revert drm/amd/display: Enable Freesync Video Mode by default"

This reverts commit 11b92df8.

This conflicts with how compositors want to handle VRR.  Now
that compositors actually handle VRR, we probably don't need
freesync video.

Closes: drm/amd#2985


Acked-by: Hamza Mahfooz <hamza.mahfooz@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>