amdgpu_mode.h

Current design has per-crtc-plane model.
As a result, for asic's that support underlay,
are unable to expose it to user space for modesetting.

To enable this, the drm driver intialisation now runs
for number of surfaces instead of stream/crtc.

This patch plumbs surface capabilities to drm framework
so that it can be effectively used by user space.

Tests: (On Chromium OS for Stoney Only)
* 'modetest -p'  now shows additional plane
  with YUV capabilities in case of CZ and ST.
* 'plane_test' fails with below error:
  [drm:amdgpu_dm_connector_atomic_set_property [amdgpu]] *ERROR* Unsupported screen depth 0
  as ther is no support for YUYV
* Checked multimonitor display works fine

Signed-off-by: Shirish S <shirish.s@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>