drm/amd/display: Pass plane caps into amdgpu_dm_plane_init

[Why]
When deciding to add properties or expose formats on DRM planes we
should be querying the caps for the DC plane it's supposed to represent.

[How]
Pass plane caps down into plane initialization, refactoring overlay
plane initialization to have the overlay plane be represented by
the first overlay capable DC plane.

Signed-off-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Reviewed-by: Leo Li <sunpeng.li@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>