xfs: remove unused deferred ops committed field

xfs: remove unused deferred ops committed field

Source kernel commit: 83200bfac6082a46cc962366478d050052e50450

dop_committed is set when deferred item processing rolls the
transaction at least once, but is only ever accessed in tracepoints.
The transaction roll/commit events are already available via
independent tracepoints, so remove the otherwise unused field.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bill O'Donnell <billodo@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Eric Sandeen <sandeen@sandeen.net>