iommu/vt-d: Handle PCI bridge RMRR device scopes in intel_iommu_get_resv_regions

mainline inclusion
from mainline-5.3
commit 3855ba2d
category: bugfix
bugzilla: 17414
CVE: NA

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In the case the RMRR device scope is a PCI-PCI bridge, let's check
the device belongs to the PCI sub-hierarchy.

Fixes: 0659b8dc ("iommu/vt-d: Implement reserved region get/put callbacks")

Signed-off-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Xiongfeng Wang <wangxiongfeng2@huawei.com>
Reviewed-by: Hanjun Guo <guohanjun@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>