drm/doc: use preferred struct reference in kernel-doc

sed -e 's/\( \* .*\)struct &\([_a-z]*\)/\1\&struct \2/' -i

Originally I wasnt a friend of this style because I thought a
line-break between the "&struct" and "foo" part would break it. But a
quick test shows that " * &struct \n * foo\n" works pefectly well with
current kernel-doc. So time to mass-apply these changes!

Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1483044517-5770-6-git-send-email-daniel.vetter@ffwll.ch

drivers/gpu/drm/drm_irq.c

@@ -982,7 +982,7 @@ static void send_vblank_event(struct drm_device *dev,
  * period. This helper function implements exactly the required vblank arming
  * behaviour.
  *
- * NOTE: Drivers using this to send out the event in struct &drm_crtc_state
+ * NOTE: Drivers using this to send out the event in &struct drm_crtc_state
  * as part of an atomic commit must ensure that the next vblank happens at
  * exactly the same time as the atomic commit is committed to the hardware. This
  * function itself does **not** protect again the next vblank interrupt racing