iommu/vt-d: Avoid caching stale domain_device_info and fix memory leak

Function device_notifier() in intel-iommu.c fails to remove
device_domain_info data structures for PCI devices if they are
associated with si_domain because iommu_no_mapping() returns true
for those PCI devices. This will cause memory leak and caching of
stale information in domain->devices list.

So fix the issue by not calling iommu_no_mapping() and skipping check
of iommu_pass_through.

Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Signed-off-by: Joerg Roedel <joro@8bytes.org>