Looks like nobody is using fs_dax_get_by_host() except fs_dax_get_by_bdev()
and it can easily use dax_get_by_host() instead.

IIUC, fs_dax_get_by_host() was only introduced so that one could compile
with CONFIG_FS_DAX=n and CONFIG_DAX=m. fs_dax_get_by_bdev() achieves
the same purpose and hence it looks like fs_dax_get_by_host() is not
needed anymore.
Signed-off-by: NVivek Goyal <vgoyal@redhat.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20200106181117.GA16248@redhat.comSigned-off-by: NDan Williams <dan.j.williams@intel.com>