FS: Remove Link to xfs.org page.

FS: Remove Link to xfs.org page.

	Code: 500 Can't connect to xfs.org:443 (Connection timed out)

Quoting XFS developer Darrick J. Wong on lkml:

	> Is there a replacement URL for the xfs documentation?

	None that I know of.  Some of it went to xfs.org but then we lost
	control of it.  I tried to push other pieces went to xfs.wiki.kernel.org
	but then we lost control of that too.  Some of it is slowly migrating to
	the kernel source code, but most of the old stuff is probably not
	movable because people are afraid of mixing GPL and CC licensed data in
	the same git repo/git server.