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

MAINTAINERS

@@ -7941,6 +7941,7 @@ M:	Gao Xiang <xiang@kernel.org>
 M:	Chao Yu <chao@kernel.org>
 R:	Yue Hu <huyue2@coolpad.com>
 R:	Jeffle Xu <jefflexu@linux.alibaba.com>
+R:	Sandeep Dhavale <dhavale@google.com>
 L:	linux-erofs@lists.ozlabs.org
 S:	Maintained
 W:	https://erofs.docs.kernel.org