Bluetooth: Use defined link key size

Remove magic number with defined link key size.

Signed-off-by: Andrei Emeltchenko <andrei.emeltchenko@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
diff --git a/net/bluetooth/mgmt.c b/net/bluetooth/mgmt.c
index 6a7e926..1fd49e6 100644
--- a/net/bluetooth/mgmt.c
+++ b/net/bluetooth/mgmt.c
@@ -2955,7 +2955,7 @@
 	bacpy(&ev.key.addr.bdaddr, &key->bdaddr);
 	ev.key.addr.type = BDADDR_BREDR;
 	ev.key.type = key->type;
-	memcpy(ev.key.val, key->val, 16);
+	memcpy(ev.key.val, key->val, HCI_LINK_KEY_SIZE);
 	ev.key.pin_len = key->pin_len;
 
 	return mgmt_event(MGMT_EV_NEW_LINK_KEY, hdev, &ev, sizeof(ev), NULL);