MAINTAINERS: Update HiSilicon GPIO Driver maintainer

Add Jay Fang as the maintainer of the HiSilicon GPIO Driver, replacing
Luo Jiaxing.

Cc: Luo Jiaxing <jiaxingluo@autox.ai>
Signed-off-by: Jay Fang <f.fangjian@huawei.com>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Acked-by: Jiaxing Luo <jiaxingluo@autox.ai>
Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>