drm: vc4: Switch to use drm_gem_object reservation_object

Now that the base struct drm_gem_object has a reservation_object, use it
and remove the private BO one.

Cc: Eric Anholt <eric@anholt.net>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: dri-devel@lists.freedesktop.org
Signed-off-by: Rob Herring <robh@kernel.org>
5 files changed