NVMe: Fix irq freeing when queue_request_irq fails

Fixes an issue when queue_reuest_irq fails in nvme_setup_io_queues. This
patch initializes all vectors to -1 and resets the vector to -1 in the
case of a failure in queue_request_irq. This avoids the free_irq in
nvme_suspend_queue if the queue did not get an irq.

Signed-off-by: Jon Derrick <jonathan.derrick@intel.com>
Signed-off-by: Jens Axboe <axboe@fb.com>