drm/amd/display: Enable dp_hdmi21_pcon support

[Why]
It is not enabled for DCN3.0.1, 3.0.2, 3.0.3.

[How]
Add `dc->caps.dp_hdmi21_pcon_support = true` to these DCN versions.

Reviewed-by: Martin Leung <Martin.Leung@amd.com>
Acked-by: Stylon Wang <stylon.wang@amd.com>
Signed-off-by: David Galiffi <David.Galiffi@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>