Guenter reported an boot hang issue on HPPA after we default to 0 poll
queues. We have two issues in the queue count calculations:
1) We don't separate the poll queues from the read/write queues. This is
important, since the former doesn't need interrupts.
2) The adjust logic is broken.
Adjust the poll queue count before doing nvme_calc_io_queues(). The poll
queue count is only limited by the IO queue count we were able to get
from the controller, not failures in the IRQ allocation loop. This
leaves nvme_calc_io_queues() just adjusting the read/write queue map.