nvme: setup streams after initializing namespace head

Fixes a NULL pointer dereference.
Reported-by: NArnav Dawn <a.dawn@samsung.com>
Signed-off-by: NKeith Busch <keith.busch@intel.com>
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

drivers/nvme/host/core.c

@@ -2870,7 +2870,6 @@ static void nvme_alloc_ns(struct nvme_ctrl *ctrl, unsigned nsid)
 
 	blk_queue_logical_block_size(ns->queue, 1 << ns->lba_shift);
 	nvme_set_queue_limits(ctrl, ns->queue);
-	nvme_setup_streams_ns(ctrl, ns);
 
 	id = nvme_identify_ns(ctrl, nsid);
 	if (!id)
@@ -2881,6 +2880,7 @@ static void nvme_alloc_ns(struct nvme_ctrl *ctrl, unsigned nsid)
 
 	if (nvme_init_ns_head(ns, nsid, id, &new))
 		goto out_free_id;
+	nvme_setup_streams_ns(ctrl, ns);
 	
 #ifdef CONFIG_NVME_MULTIPATH
 	/*