MAINTAINERS: erofs: add myself as reviewer

I have been contributing to erofs for sometime and I would like to help
with code reviews as well.

Signed-off-by: Sandeep Dhavale <dhavale@google.com>
Acked-by: Chao Yu <chao@kernel.org>
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20240314231407.1000541-1-dhavale@google.com


Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>