MAINTAINERS: drop me as XFS maintainer

MAINTAINERS: drop me as XFS maintainer

I burned out years ago trying to juggle the roles senior developer,
reviewer, tester, triager (crappily), release manager, and (at times)
manager liaison.  There's enough work here in this one subsystem for a
team of 20 FT, but instead we're squeezed to half that.  I thought if I
could hold on just a bit longer I could help to maintain the focus on
long term development to improve the experience for users.  I was wrong.

Nowadays, people working on XFS seem to spend most of their time on
distro kernel backports and dealing with AI-generated corner case bug
reports that aren't user reports.  Reviewing has become a nightmare of
sifting through under-documented kernel code trying to decide if this
new feature won't break all the other features.  Getting reviews is an
unpleasant process of negotiating with demands for further cleanups,
trying to figure out if a review comment is based in experience or
unfamiliarity, and wondering if the silence means anything.

For now, I will continue to review patches and will try to get online
fsck, parent pointers, and realtime volume modernisation merged.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>