8ccf0e2076
[why] When display is connected with a native DP port, DP2 mode register value is a don't care. Driver mistakenly reduce max supported lane count to 2 lane based on the don't care value. [how] Add additional check only if USB C DP alt mode is enabled, we will determine max lane count supported based on current mode. Signed-off-by: Wenjing Liu <wenjing.liu@amd.com> Reviewed-by: Aric Cyr <Aric.Cyr@amd.com> Acked-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com> Signed-off-by: Alex Deucher <alexander.deucher@amd.com>