regulator: hi6421v600-regulator: add a missing dot at copyright

The Huawei's copyright is missing a dot at the end. Add it,
in order to make it similar to the other two copyrights.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/e9c0f27688d7be75652800e67c913878fd772cbe.1625211021.git.mchehab+huawei@kernel.org


Signed-off-by: Mark Brown <broonie@kernel.org>