[media] em28xx: set the timestamp type for video and vbi vb2_queues

The em28xx driver obtains the timestamps using function v4l2_get_timestamp(),
which produces a montonic timestamp.
Fixes the warnings appearing in the system log since commit 6aa69f99
"[media] vb2: Add support for non monotonic timestamps"

Signed-off-by: Frank Schäfer <fschaefer.oss@googlemail.com>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/usb/em28xx/em28xx-video.c

@@ -700,6 +700,7 @@ int em28xx_vb2_setup(struct em28xx *dev)
 	q = &dev->vb_vidq;
 	q->type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
 	q->io_modes = VB2_READ | VB2_MMAP | VB2_USERPTR | VB2_DMABUF;
+	q->timestamp_type = V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC;
 	q->drv_priv = dev;
 	q->buf_struct_size = sizeof(struct em28xx_buffer);
 	q->ops = &em28xx_video_qops;
@@ -713,6 +714,7 @@ int em28xx_vb2_setup(struct em28xx *dev)
 	q = &dev->vb_vbiq;
 	q->type = V4L2_BUF_TYPE_VBI_CAPTURE;
 	q->io_modes = VB2_READ | VB2_MMAP | VB2_USERPTR;
+	q->timestamp_type = V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC;
 	q->drv_priv = dev;
 	q->buf_struct_size = sizeof(struct em28xx_buffer);
 	q->ops = &em28xx_vbi_qops;