NVMe: removed unused nn var from nvme_dev_add

The logic in nvme_dev_add to enumerate namespaces was moved to
nvme_dev_scan. When moved, the nn variable is no longer used. This patch
removes it.

Fixes: a5768aa8i ("NVMe: Automatic namespace rescan")
Signed-off-by: NMatias Bjørling <m@bjorling.me>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@fb.com>

drivers/block/nvme-core.c

@@ -2447,7 +2447,6 @@ static int nvme_dev_add(struct nvme_dev *dev)
 {
 	struct pci_dev *pdev = to_pci_dev(dev->dev);
 	int res;
-	unsigned nn;
 	struct nvme_id_ctrl *ctrl;
 	int shift = NVME_CAP_MPSMIN(readq(&dev->bar->cap)) + 12;
 
@@ -2457,7 +2456,6 @@ static int nvme_dev_add(struct nvme_dev *dev)
 		return -EIO;
 	}
 
-	nn = le32_to_cpup(&ctrl->nn);
 	dev->oncs = le16_to_cpup(&ctrl->oncs);
 	dev->abort_limit = ctrl->acl + 1;
 	dev->vwc = ctrl->vwc;