xfs: disable sb_frextents for zoned file systems

Zoned file systems not only don't use the global frextents counter, but
for them the in-memory percpu counter also includes reservations taken
before even allocating delalloc extent records, so it will never match
the per-zone used information.  Disable all updates and verification of
the sb counter for zoned file systems as it isn't useful for them.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>