Add sunxi v4l2 rotation engine support to the drm_hwcomposer

[rsglobal]

Sunxi display controlled has no support for rotated planes.
Instead it offers separate IP core to rotate buffer, which is exposed to user as v4l2 driver.

To off-load GPU with changed orientation, we can use that driver.

Case 1: No rotation
[hwc layer 1] -> [drm_plane 1]
[hwc layer 2] -> [drm_plane 2]

Case 2: Changed orientation

[hwc layer 1] -> [Rotate layer into new buffer, cache it] -> [drm_plane 1]
[hwc layer 2] -> [Rotate layer into new buffer, cache it] -> [drm_plane 2]

[rsglobal]

Link to the driver: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/drivers/media/platform/sunxi/sun8i-rotate?h=v5.9-rc2&id=d77182ada3d40854735eb9321ce30de60c2abdbb

[rsglobal]

@matviizorin

Assignment removed due to long inactivity. Please update it if you are still working on the issue.