This allows the per device iommu data and some helpers to be
used in other files.

Cc: Ashok Raj <ashok.raj@intel.com>
Cc: Jacob Pan <jacob.jun.pan@linux.intel.com>
Cc: Kevin Tian <kevin.tian@intel.com>
Cc: Liu Yi L <yi.l.liu@intel.com>
Signed-off-by: NLu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: NLiu Yi L <yi.l.liu@intel.com>
Signed-off-by: NJoerg Roedel <jroedel@suse.de>