v4l2: do not warn about unsupported CROPCAP, only print debug

CROPCAP is no longer mandatory, and many drivers failed to provide it.
If there is no CROPCAP, then there is no cropping.

modules/access/v4l2/video.c

@@ -216,8 +216,8 @@ static int ResetCrop (vlc_object_t *obj, int fd)
      * In practice, it does not. */
     if (v4l2_ioctl (fd, VIDIOC_CROPCAP, &cropcap) < 0)
     {
-        msg_Warn (obj, "cannot get cropping properties: %m");
-        return -1;
+        msg_Dbg (obj, "cannot get cropping properties: %m");
+        return 0;
     }
 
     /* Reset to the default cropping rectangle */