physmem: register region with IOMMU
physmem: register region with IOMMU

VFIO file descriptor is extracted in a hackish way, as DPDK doesn't
provide imethod to retrieve it.

This fixes issue with DPDK drivers not working correctly when IOMMU is
enabled and external buffer memory is used.

Change-Id: I5eaa8e78741c50504d87d44e706b5997c8189554
Signed-off-by: Damjan Marion <9141bba8b2efed526e55cf796d48631af330ad98@cisco.com>

FDio/vpp,chrisy/vpp,chrisy/vpp,FDio/vpp,chrisy/vpp,FDio/vpp,vpp-dev/vpp,chrisy/vpp,chrisy/vpp,FDio/vpp,chrisy/vpp,FDio/vpp,chrisy/vpp,vpp-dev/vpp,FDio/vpp,chrisy/vpp,vpp-dev/vpp,vpp-dev/vpp,vpp-dev/vpp,vpp-dev/vpp,FDio/vpp,vpp-dev/vpp,FDio/vpp