i2c: hix5hd2: use the correct HiSilicon copyright

s/Hisilicon/HiSilicon/g.
It should use capital S, according to
https://www.hisilicon.com/en/terms-of-use

.

Signed-off-by: Hao Fang <fanghao11@huawei.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>