nvme-pci: remove unnecessary completion doorbell check

The nvme pci driver never unmaps the doorbell registers while the requests
are active, so we can always safely update the completion queue head.
Signed-off-by: Keith Busch <keith.busch@intel.com>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

drivers/nvme/host/pci.c

@@ -920,11 +920,9 @@ static inline void nvme_ring_cq_doorbell(struct nvme_queue *nvmeq)
 {
 	u16 head = nvmeq->cq_head;
 
-	if (likely(nvmeq->cq_vector >= 0)) {
 	if (nvme_dbbuf_update_and_check_event(head, nvmeq->dbbuf_cq_db,
 					      nvmeq->dbbuf_cq_ei))
 		writel(head, nvmeq->q_db + nvmeq->dev->db_stride);
-	}
 }
 
 static inline void nvme_handle_cqe(struct nvme_queue *nvmeq, u16 idx)