s390/ap: rework to use irq info from ap queue status

This patch reworks the irq handling and reporting code
for the AP queue interrupt handling to always use the
irq info from the queue status.

Until now the interrupt status of an AP queue was stored
into a bool variable within the ap_queue struct. This
variable was set on a successful interrupt enablement
and cleared with kicking a reset. However, it may be
that the interrupt state is manipulated outband for
example by a hypervisor. This patch removes this variable
and instead the irq bit from the AP queue status which is
always reflecting the current irq state is used.

Reviewed-by: Tony Krowiak <akrowiak@linux.ibm.com>
Reviewed-by: Holger Dengler <dengler@linux.ibm.com>
Signed-off-by: Harald Freudenberger <freude@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>