Changing the deliverable mask in __airqs_kick_single_vcpu() is a bug. If
one idle vcpu can't take the interrupts we want to deliver, we should
look for another vcpu that can, instead of saying that we don't want
to deliver these interrupts by clearing the bits from the
deliverable_mask.

Fixes: 9f30f621 ("KVM: s390: add gib_alert_irq_handler()")
Signed-off-by: NHalil Pasic <pasic@linux.ibm.com>
Reviewed-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: NMichael Mueller <mimu@linux.ibm.com>
Reviewed-by: NClaudio Imbrenda <imbrenda@linux.ibm.com>
Link: https://lore.kernel.org/r/20211019175401.3757927-3-pasic@linux.ibm.comSigned-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>