Bluetooth: Fix bt_sock_recvmsg when MSG_TRUNC is not set

Commit b5f34f94 attempt to introduce
proper handling for MSG_TRUNC but recv and variants should still work
as read if no flag is passed, but because the code may set MSG_TRUNC to
msg->msg_flags that shall not be used as it may cause it to be behave as
if MSG_TRUNC is always, so instead of using it this changes the code to
use the flags parameter which shall contain the original flags.
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

net/bluetooth/af_bluetooth.c

@@ -250,7 +250,7 @@ int bt_sock_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
 
 	skb_free_datagram(sk, skb);
 
-	if (msg->msg_flags & MSG_TRUNC)
+	if (flags & MSG_TRUNC)
 		copied = skblen;
 
 	return err ? : copied;