media: h264: Avoid wrapping long_term_frame_idx

For long term references, frame_num is set to long_term_frame_idx which
does not require wrapping. This is fixed by observation, no directly
related issue have been found yet.
Signed-off-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
Reviewed-by: Sebastian Fricke <sebastian.fricke@collabora.com>
Reviewed-by: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

drivers/media/v4l2-core/v4l2-h264.c

@@ -57,8 +57,10 @@ v4l2_h264_init_reflist_builder(struct v4l2_h264_reflist_builder *b,
 		 * '8.2.4.1 Decoding process for picture numbers' of the spec.
 		 * TODO: This logic will have to be adjusted when we start
 		 * supporting interlaced content.
+		 * For long term references, frame_num is set to
+		 * long_term_frame_idx which requires no wrapping.
 		 */
-		if (dpb[i].frame_num > cur_frame_num)
+		if (!b->refs[i].longterm && dpb[i].frame_num > cur_frame_num)
 			b->refs[i].frame_num = (int)dpb[i].frame_num -
 					       max_frame_num;
 		else