drm/atomic: Call fake_vblank() from the generic commit_tail() helpers

Now that we have a way to fake VBLANK events when requested by the CRTC
hook it up to the generic commit_tail() helpers.
Signed-off-by: NBoris Brezillon <boris.brezillon@bootlin.com>
Reviewed-by: NLiviu Dudau <liviu.dudau@arm.com>
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20180703075022.15138-7-boris.brezillon@bootlin.com

drivers/gpu/drm/drm_atomic_helper.c

@@ -1450,6 +1450,8 @@ void drm_atomic_helper_commit_tail(struct drm_atomic_state *old_state)
 
 	drm_atomic_helper_commit_modeset_enables(dev, old_state);
 
+	drm_atomic_helper_fake_vblank(old_state);
+
 	drm_atomic_helper_commit_hw_done(old_state);
 
 	drm_atomic_helper_wait_for_vblanks(dev, old_state);
@@ -1479,6 +1481,8 @@ void drm_atomic_helper_commit_tail_rpm(struct drm_atomic_state *old_state)
 	drm_atomic_helper_commit_planes(dev, old_state,
 					DRM_PLANE_COMMIT_ACTIVE_ONLY);
 
+	drm_atomic_helper_fake_vblank(old_state);
+
 	drm_atomic_helper_commit_hw_done(old_state);
 
 	drm_atomic_helper_wait_for_vblanks(dev, old_state);