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

Remove buffer type checking from vino_g_parm(), vino_s_parm(),
vino_reqbufs(), vino_querybuf(), vino_qbuf(), and vino_dqbuf().  This
reduced the indent level of the code so a few lines can be wrapped better.
Also fixed the C++ type comments.

The v4l2-ioctl core also provides structs that have been pre-zeroed for all
fields that driver is supposed to fill in, so remove zeroing code from
vino_enum_fmt_vid_cap().  Also, the format index is unsigned so it's not
necessary to check if it's less than zero.
Signed-off-by: Trent Piepho <xyzzy@speakeasy.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>