x86_iommu/amd: Add interrupt remap support when VAPIC is not enabled

x86_iommu/amd: Add interrupt remap support when VAPIC is not enabled

Emulate the interrupt remapping support when guest virtual APIC is
not enabled.

For more info Refer: AMD IOMMU spec Rev 3.0 - section 2.2.5.1

When VAPIC is not enabled, it uses interrupt remapping as defined in
Table 20 and Figure 15 from IOMMU spec.

Signed-off-by: Brijesh Singh <[email protected]>
Cc: Peter Xu <[email protected]>
Cc: "Michael S. Tsirkin" <[email protected]>
Cc: Paolo Bonzini <[email protected]>
Cc: Richard Henderson <[email protected]>
Cc: Eduardo Habkost <[email protected]>
Cc: Marcel Apfelbaum <[email protected]>
Cc: Tom Lendacky <[email protected]>
Cc: Suravee Suthikulpanit <[email protected]>
Reviewed-by: Peter Xu <[email protected]>
Reviewed-by: Michael S. Tsirkin <[email protected]>
Signed-off-by: Michael S. Tsirkin <[email protected]>