drm/amdgpu: skip TV/CV in display parsing

No asics supported by amdgpu support analog TV.

Workaround for bug:
https://bugs.freedesktop.org/show_bug.cgi?id=97460

Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org