xfs: add new IRC channel to MAINTAINERS

Add our new OFTC channel to the MAINTAINERS list so everyone will know
where to go.  Ignore the XFS wikis, we have no access to them.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Brian Foster <bfoster@redhat.com>

MAINTAINERS

@@ -19998,6 +19998,7 @@ F:	arch/x86/xen/*swiotlb*
 F:	drivers/xen/*swiotlb*
 
 XFS FILESYSTEM
+C:	irc://irc.oftc.net/xfs
 M:	Darrick J. Wong <djwong@kernel.org>
 M:	linux-xfs@vger.kernel.org
 L:	linux-xfs@vger.kernel.org