drm: rcar-du: Fix framebuffer reference leak through plane state
drm: rcar-du: Fix framebuffer reference leak through plane state

Plane state duplication takes a reference to the framebuffer stored in
the state, but state destroy doesn't release it. This causes a reference
leak. Fix it.

Signed-off-by: Laurent Pinchart <ae960578cc5eca7b9b1dbc37d9caa6cb634f35e0@ideasonboard.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs