staging: hikey9xx: hi6421v600-regulator: update copyright

Remove the GPL boilerplate, as SPDX tag already points to the
license terms and add a new copyright for Huawei.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/80d2d21c3d327e3acc89d016b20bd2d93e9c6f65.1611212783.git.mchehab+huawei@kernel.org


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>