The SPDX header is missing, let's add it and fix the corresponding
checkpatch warning.
Suggested-by: Maíra Canal <mairacanal@riseup.net>
Fixes: 44a3928324 ("drm/tests: Add Kunit Helpers")
Reviewed-by: Maíra Canal <mairacanal@riseup.net>
Link: https://lore.kernel.org/r/20221116151833.1679379-2-maxime@cerno.tech
Signed-off-by: Maxime Ripard <maxime@cerno.tech>