drivers/gpu/drm/i915/intel_overlay.c needs seq_file.h

drivers/gpu/drm/i915/intel_overlay.c: In function 'intel_overlay_print_error_state':

drivers/gpu/drm/i915/intel_overlay.c:1467: error: implicit declaration of function 'seq_printf'

Addresses https://bugzilla.kernel.org/show_bug.cgi?id=16811

Reported-by: Martin Ziegler <ziegler@uni-freiburg.de>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Eric Anholt <eric@anholt.net>
Cc: Dave Airlie <airlied@linux.ie>
Cc: Andre Muller <andremuellerster@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

drivers/gpu/drm/i915/intel_overlay.c

@@ -25,6 +25,8 @@
  *
  * Derived from Xorg ddx, xf86-video-intel, src/i830_video.c
  */
+
+#include <linux/seq_file.h>
 #include "drmP.h"
 #include "drm.h"
 #include "i915_drm.h"