Adds v4l2_std_id, struct v4l2_standard/v4l2_plane, VIDIOC_G_STD/S_STD/
ENUMSTD, V4L2_STD_NTSC*, the MPLANE capability flag, multiplanar types
(VIDEO_MAX_PLANES, v4l2_plane_pix_format, v4l2_pix_format_mplane,
V4L2_TYPE_IS_MULTIPLANAR), V4L2_PIX_FMT_JPEG/YUV411P/SN9C10X, and the
MPEG control class (V4L2_CID_MPEG_BASE, V4L2_CID_MPEG_VIDEO_B_FRAMES).
video(4) capture devices are digital-only and never expose these, but
ffmpeg's libavdevice/v4l2.c and opencv's cap_v4l.cpp both reference
them unconditionally. Fixes their build against sys/videoio.h.
PR: 297454