ocfs2: remove ocfs2_reflink_remap_range

Since ocfs2_remap_file_range is a thin shell around
ocfs2_remap_remap_range, move everything from the latter into the
former.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>