drm/amd/display: Report Freesync to vrr_range debugfs entry in DRM

[Why]
Since Linux 5.9.0, DRM has provided vrr_range debugfs for
all connectors. Reporting Freesync capability to vrr_range
debugfs entry registered in Linux DM no longer works.

[How]
Report min/max vertical frequency to vrr_range debugfs entrry
created by DRM connectors. Remove vrr_range debugfs entry from
Linux DM.

Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Stylon Wang <stylon.wang@amd.com>
Reviewed-by: Nicholas Kazlauskas <Nicholas.Kazlauskas@amd.com>
Acked-by: Anson Jacob <anson.jacob@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>