V4L/DVB (8921): ivtv: fix incorrect capability and assorted sliced vbi and video out fmt fixes

- V4L2_CAP_VBI_OUTPUT is not supported by ivtv, remove it.
- ivtv_try_fmt_vid_out also needed to constrain the width/height of MPEG decoder
  window sizes.
- allow empty sliced services.

Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/drivers/media/video/ivtv/ivtv-cards.h b/drivers/media/video/ivtv/ivtv-cards.h
index 381af1b..0b8fe85 100644
--- a/drivers/media/video/ivtv/ivtv-cards.h
+++ b/drivers/media/video/ivtv/ivtv-cards.h
@@ -154,7 +154,7 @@
 #define IVTV_CAP_ENCODER (V4L2_CAP_VIDEO_CAPTURE | V4L2_CAP_TUNER | \
 			  V4L2_CAP_AUDIO | V4L2_CAP_READWRITE | V4L2_CAP_VBI_CAPTURE | \
 			  V4L2_CAP_SLICED_VBI_CAPTURE)
-#define IVTV_CAP_DECODER (V4L2_CAP_VBI_OUTPUT | V4L2_CAP_VIDEO_OUTPUT | \
+#define IVTV_CAP_DECODER (V4L2_CAP_VIDEO_OUTPUT | \
 			  V4L2_CAP_SLICED_VBI_OUTPUT | V4L2_CAP_VIDEO_OUTPUT_OVERLAY)
 
 struct ivtv_card_video_input {