pci: Add a PCI-level API for PRI

pci: Add a PCI-level API for PRI

A device can send a PRI request to the IOMMU using pci_pri_request_page.
The PRI response is sent back using the notifier managed with
pci_pri_register_notifier and pci_pri_unregister_notifier.

Signed-off-by: Clement Mathieu--Drif <clement.mathieu--drif@eviden.com>
Co-authored-by: Ethan Milon <ethan.milon@eviden.com>
Message-Id: <20250520071823.764266-12-clement.mathieu--drif@eviden.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>