x86/apic/x2apic: set affinity of a single interrupt to one cpu

x86/apic/x2apic: set affinity of a single interrupt to one cpu

Customer want to offline the cpus to 2 per node. And finally, a
lpfc HBA cannot work any more due to no available
irq vectors.
[   51.031812] IRQ 284 set affinity failed because there are no available vectors.  The device assigned to this IRQ is unstable.
[   51.031817] IRQ 285 set affinity failed because there are no available vectors.  The device assigned to this IRQ is unstable.
[   51.031822] IRQ 286 set affinity failed because there are no available vectors.  The device assigned to this IRQ is unstable.
[   51.031827] IRQ 287 set affinity failed because there are no available vectors.  The device assigned to this IRQ is unstable.

It was due to cluster_vector_allocation_domain which want to set
interrupt affinity of a single interrupt to multiple CPUs and need
a same irq vector to be available on multiple cpus. This is difficult
for customer's case where there are a lot of HBAs on node 0 and only
2 or 4 cpus online there.

And actually, this feature has been discarded by the upstream.
https://lkml.org/lkml/2017/9/13/576
We close this feature by just set one cpu in retmask in
cluster_vector_allocation_domain.

Customer that encountered this issue used RHCK, since UEK4 also
has the same code, post a same patch for UEK4

Orabug: 29196396

Reviewed-by: Zhenzhong Duan <zhenzhong.duan@oracle.com>
Signed-off-by: Jianchao Wang <jianchao.w.wang.oracle.com>
Signed-off-by: Brian Maly <brian.maly@oracle.com>