vfs: plumb remap flags through the vfs dedupe functions

Plumb a remap_flags argument through the vfs_dedupe_file_range_one
functions so that dedupe can take advantage of it.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>