media: v4l2-dev/ioctl: Fix document for VIDIOC_QUERYCAP

V4L2_CAP_VIDEO_M2M is documented as 0x00004000
V4L2_CAP_VIDEO_M2M_MPLANE is documented as 0x00008000
This is different from the definition in include/uapi/linux/videodev2.h

Signed-off-by: Jian-Jia Su <jjsu@chromium.org>
Reviewed-by: Helen Koike <helen.koike@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>