MAINTAINERS: add Carlos Maiolino as XFS release manager

I nominate Carlos Maiolino to take over linux-xfs tree maintainer role for
upstream kernel's XFS code. He has enough experience in Linux kernel and he's
been maintaining xfsprogs and xfsdump trees for a few years now, so he has
sufficient experience with xfs workflow to take over this role.

Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>
Acked-by: Carlos Maiolino <cem@kernel.org>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Carlos Maiolino <cem@kernel.org>