KVM: s390: pci: enable host forwarding of Adapter Event Notifications

KVM: s390: pci: enable host forwarding of Adapter Event Notifications

In cases where interrupts are not forwarded to the guest via firmware,
KVM is responsible for ensuring delivery.  When an interrupt presents
with the forwarding bit, we must process the forwarding tables until
all interrupts are delivered.

Reviewed-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Reviewed-by: Pierre Morel <pmorel@linux.ibm.com>
Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com>
Link: https://lore.kernel.org/r/20220606203325.110625-14-mjrosato@linux.ibm.com
Signed-off-by: Christian Borntraeger <borntraeger@linux.ibm.com>