On older kernels that don't have VFIO, stub out the vhost IOMMU
functions.
Fixes build on older distributions (e.g. CentOS 6).
Change-Id: Icda9998e494c24d252511a4da93ecb56502fe5a7
Signed-off-by: Daniel Verkamp <daniel.verkamp@intel.com>
Reviewed-on: https://review.gerrithub.io/363473
Tested-by: SPDK Automated Test System <sys_sgsw@intel.com>
Reviewed-by: Pawel Wodkowski <pawelx.wodkowski@intel.com>
Reviewed-by: Ben Walker <benjamin.walker@intel.com>