drm/exynos: remove unnecessary code.

plane->fb will be set to new fb after update_plane callback is called
by drm_mode_set_plane()
Signed-off-by: NInki Dae <inki.dae@samsung.com>
Signed-off-by: NKyungmin Park <kyungmin.park@samsung.com>

drivers/gpu/drm/exynos/exynos_drm_plane.c

@@ -204,7 +204,6 @@ exynos_update_plane(struct drm_plane *plane, struct drm_crtc *crtc,
 		return ret;
 
 	plane->crtc = crtc;
-	plane->fb = crtc->fb;
 
 	exynos_plane_commit(plane);
 	exynos_plane_dpms(plane, DRM_MODE_DPMS_ON);