nvme: use define instead of magic value for identify size

NVME_IDENTIFY_DATA_SIZE was added to linux/nvme.h by following commit.
  commit 0add5e8e ("nvmet: use NVME_IDENTIFY_DATA_SIZE")

Make it use NVME_IDENTIFY_DATA_SIZE define instead of magic value
0x1000 in case of identify data size.
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Minwoo Im <minwoo.im.dev@gmail.com>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

drivers/nvme/host/core.c

@@ -948,7 +948,8 @@ static int nvme_identify_ns_list(struct nvme_ctrl *dev, unsigned nsid, __le32 *n
 	c.identify.opcode = nvme_admin_identify;
 	c.identify.cns = NVME_ID_CNS_NS_ACTIVE_LIST;
 	c.identify.nsid = cpu_to_le32(nsid);
-	return nvme_submit_sync_cmd(dev->admin_q, &c, ns_list, 0x1000);
+	return nvme_submit_sync_cmd(dev->admin_q, &c, ns_list,
+				    NVME_IDENTIFY_DATA_SIZE);
 }
 
 static struct nvme_id_ns *nvme_identify_ns(struct nvme_ctrl *ctrl,
@@ -3109,7 +3110,7 @@ static int nvme_scan_ns_list(struct nvme_ctrl *ctrl, unsigned nn)
 	unsigned i, j, nsid, prev = 0, num_lists = DIV_ROUND_UP(nn, 1024);
 	int ret = 0;
 
-	ns_list = kzalloc(0x1000, GFP_KERNEL);
+	ns_list = kzalloc(NVME_IDENTIFY_DATA_SIZE, GFP_KERNEL);
 	if (!ns_list)
 		return -ENOMEM;