intel-iommu: Check IOAPIC's Trigger Mode against the one in IRTE

The Trigger Mode field of IOAPIC must match the Trigger Mode in
the IRTE according to VT-d Spec 5.1.5.1.

Signed-off-by: Feng Wu <feng.wu@intel.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
