drm/amd/display: Check for DP2.0 when checking ODM combine

[WHY]
Certain DP 2.0 modes may fail validation if DP 2.0 is not considered for
ODM combine.

Reviewed-by: Wenjing Liu <Wenjing.Liu@amd.com>
Acked-by: Solomon Chiu <solomon.chiu@amd.com>
Signed-off-by: Wesley Chalmers <Wesley.Chalmers@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>