drm/atomic-helper: Fix reference to drm_crtc_send_vblank_event()

Fix up this reference so that the proper link is generated in the
documentation and so that people don't go chasing after the wrong
function for an embarrassingly long time.
Acked-by: Noralf Trønnes <noralf@tronnes.org>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171012140857.9559-1-thierry.reding@gmail.com

drivers/gpu/drm/drm_atomic_helper.c

@@ -1819,7 +1819,7 @@ EXPORT_SYMBOL(drm_atomic_helper_setup_commit);
  * This function waits for all preceeding commits that touch the same CRTC as
  * @old_state to both be committed to the hardware (as signalled by
  * drm_atomic_helper_commit_hw_done) and executed by the hardware (as signalled
- * by calling drm_crtc_vblank_send_event() on the &drm_crtc_state.event).
+ * by calling drm_crtc_send_vblank_event() on the &drm_crtc_state.event).
  *
  * This is part of the atomic helper support for nonblocking commits, see
  * drm_atomic_helper_setup_commit() for an overview.