V4L/DVB (11269): cx88-blackbird: Stop setting buffer type in XXX_fmt_vid_cap

The ->vidioc_(s|g|try|enum)_fmt_vid_cap() methods are only called on
VIDEO_CAPTURE buffers.  Thus, there is no need to check or set the 'type'
field since it must already be set to VIDEO_CAPTURE.

Signed-off-by: Trent Piepho <xyzzy@speakeasy.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>