nvme: fix merge error due to change of 'make_request_fn' fn type

The type of 'make_request_fn' changed in 5a7bbad2 ("block: remove
support for bio remapping from ->make_request"), but the merge of the
nvme driver didn't take that into account, and as a result the driver
would compile with a warning:

  drivers/block/nvme.c: In function 'nvme_alloc_ns':
  drivers/block/nvme.c:1336:2: warning: passing argument 2 of 'blk_queue_make_request' from incompatible pointer type [enabled by default]
  include/linux/blkdev.h:830:13: note: expected 'void (*)(struct request_queue *, struct bio *)' but argument is of type 'int (*)(struct request_queue *, struct bio *)'

It's benign, but the warning is annoying.
Reported-by: Stephen Rothwell <sfr@canb.auug.org>
Cc: Matthew Wilcox <matthew.r.wilcox@intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/block/nvme.c

@@ -613,11 +613,7 @@ static int nvme_submit_bio_queue(struct nvme_queue *nvmeq, struct nvme_ns *ns,
 	return result;
 }
 
-/*
- * NB: return value of non-zero would mean that we were a stacking driver.
- * make_request must always succeed.
- */
-static int nvme_make_request(struct request_queue *q, struct bio *bio)
+static void nvme_make_request(struct request_queue *q, struct bio *bio)
 {
 	struct nvme_ns *ns = q->queuedata;
 	struct nvme_queue *nvmeq = get_nvmeq(ns->dev);
@@ -634,8 +630,6 @@ static int nvme_make_request(struct request_queue *q, struct bio *bio)
 
 	spin_unlock_irq(&nvmeq->q_lock);
 	put_nvmeq(nvmeq);
-
-	return 0;
 }
 
 static irqreturn_t nvme_process_cq(struct nvme_queue *nvmeq)