The v4l2-ioctl core only allows buffer types for which the corresponding
->vidioc_try_fmt_xxx() methods are defined to be used with
vidioc_(q|dq|query)bufs(), vidioc_reqbufs() and now vidioc_(s|g)_parm.

The driver was only allowing VIDEO_CAPTURE buffers for g_parm, but since
the driver defines ->vidioc_try_fmt_vid_overlay() and
->vidioc_try_fmt_vbi_cap() it will now allow VIDEO_OVERLAY and VBI_CAPTURE
buffers as well.  This should be fine as the driver only fills in the frame
rate field, which is just as valid for video overlay and vbi capture as it
is for video capture.
Signed-off-by: Trent Piepho <xyzzy@speakeasy.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>