xfs: refactor data device extent validation

Refactor all the open-coded validation of non-static data device extents
into a single helper.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
8 files changed