linux-next: build warning after merge of the drm tree

Hi all,

After merging the drm tree, today's linux-next build (arm
multi_v7_defconfig) produced this warning:

drivers/gpu/drm/rockchip/rockchip_drm_vop.c: In function 'vop_plane_atomic_update':
drivers/gpu/drm/rockchip/rockchip_drm_vop.c:882:26: warning: unused variable 'old_state' [-Wunused-variable]
  882 |  struct drm_plane_state *old_state = drm_atomic_get_old_plane_state(state,
      |                          ^~~~~~~~~

Introduced by commit

  977697e20b3d ("drm/atomic: Pass the full state to planes atomic disable and update")

-- 
Cheers,
Stephen Rothwell