vhost-vdpa: Allow transparent MSI IOV

virt inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I86ITO



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When attach dma_dev to iommu domain, check the device's
reserved regions and test whether the IOMMU translates
MSI transactions. If yes, we initialize an IOVA allocator
through the iommu_get_msi_cookie API. This will allow the
MSI IOVAs to be transparently allocated on MSI controller's
compose().

Signed-off-by: jiangdongxu <jiangdongxu1@huawei.com>