[media] v4l2-common: add v4l_match_dv_timings

Add the v4l_match_dv_timings function that can be used to compare two
v4l2_dv_timings structs.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/include/media/v4l2-common.h b/include/media/v4l2-common.h
index 4404829..447f4b6 100644
--- a/include/media/v4l2-common.h
+++ b/include/media/v4l2-common.h
@@ -212,4 +212,8 @@
 		const struct v4l2_discrete_probe *probe,
 		s32 width, s32 height);
 
+bool v4l_match_dv_timings(const struct v4l2_dv_timings *t1,
+			  const struct v4l2_dv_timings *t2,
+			  unsigned pclock_delta);
+
 #endif /* V4L2_COMMON_H_ */