xfs: pass the mapping flags to xfs_bmbt_to_iomap

To prepare for looking at the IOMAP_DAX flag in xfs_bmbt_to_iomap pass in
the input mapping flags to xfs_bmbt_to_iomap.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Link: https://lore.kernel.org/r/20211129102203.2243509-24-hch@lst.de


Signed-off-by: Dan Williams <dan.j.williams@intel.com>