Bluetooth: Use __constant modifier for L2CAP SMP CID

Since the L2CAP_CID_SMP is constant, __constant_cpu_to_le16() is
the right go here.
Signed-off-by: NSyam Sidhardhan <s.syam@samsung.com>
Acked-by: NMarcel Holtmann <marcel@holtmann.org>
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>

net/bluetooth/smp.c

@@ -165,7 +165,7 @@ static struct sk_buff *smp_build_cmd(struct l2cap_conn *conn, u8 code,
 
 	lh = (struct l2cap_hdr *) skb_put(skb, L2CAP_HDR_SIZE);
 	lh->len = cpu_to_le16(sizeof(code) + dlen);
-	lh->cid = cpu_to_le16(L2CAP_CID_SMP);
+	lh->cid = __constant_cpu_to_le16(L2CAP_CID_SMP);
 
 	memcpy(skb_put(skb, sizeof(code)), &code, sizeof(code));