V4L/DVB (11272): zr364xx: Remove code for things already done by video_ioctl2

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 buffer's
'type' field since it must already be set to VIDEO_CAPTURE.  Checking the
buffer type can be removed from zr364xx_vidioc_(s|g|try|enum)_fmt_vid_cap().

The v4l2 core code in v4l2_ioctl will zero out the structure the driver is
supposed to fill in for read-only ioctls.  For read/write ioctls, all the
fields which aren't supplied from userspace will be zeroed out.

Zeroing code can be removed from zr364xx_vidioc_querycap(),
zr364xx_vidioc_enum_input(), zr364xx_vidioc_enum_fmt_vid_cap(), and
zr364xx_vidioc_g_fmt_vid_cap().

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