media: staging: ipu3: uapi: Add "WITH Linux-syscall-note" license

All Linux headers licensed under the GPL-2.0 must include a "WITH
Linux-syscall-note" extension in their SPDX license identifier, as
enforced by the scripts/headers_install.sh script. Fix the Intel IPU3
UAPI header currently stored with the driver in staging.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>