V4L/DVB: uvcvideo: Support menu controls in the control mapping API

The UVCIOC_CTRL_MAP ioctl doesn't support menu entries for menu
controls. As the uvc_xu_control_mapping structure has no reserved
fields, this can't be fixed while keeping ABI compatibility.

Modify the UVCIOC_CTRL_MAP ioctl to add menu entries support, and define
UVCIOC_CTRL_MAP_OLD that supports the old ABI without any ability to add
menu controls.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>