iommu: make use of type-safe DFN and MFN in exported functions

iommu: make use of type-safe DFN and MFN in exported functions

This patch modifies the declaration of the entry points to the IOMMU
sub-system to use dfn_t and mfn_t in place of unsigned long. A subsequent
patch will similarly modify the methods in the iommu_ops structure.

Signed-off-by: Paul Durrant <paul.durrant@citrix.com>
Reviewed-by: Wei Liu <wei.liu2@citrix.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Roger Pau Monne <roger.pau@citrix.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Julien Grall <julien.grall@arm.com>
Reviewed-by: George Dunlap <george.dunlap@citrix.com>