xfs: remove duplicate Zoned Filesystems sections in admin-guide

Remove the duplicated section and while at it, turn spaces into tabs.

Signed-off-by: Hans Holmberg <hans.holmberg@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
Fixes: c7b67ddc ("xfs: document zoned rt specifics in admin-guide")
Signed-off-by: Carlos Maiolino <cem@kernel.org>