kvm/apic: fix 2.2->2.1 migration

kvm/apic: fix 2.2->2.1 migration

The wait_for_sipi field is set back to 1 after an INIT, so it was not
effective to reset it in kvm_apic_realize.  Introduce a reset callback
and reset wait_for_sipi there.

Reported-by: Igor Mammedov <imammedo@redhat.com>
Cc: qemu-stable@nongnu.org
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
(cherry picked from commit 575a6f4082c45778b93032ef1e7fbea4467b3a2a)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>