Revert "mptcp: fix possible divide by zero in recvmsg()"

This reverts commit 42ff95b4bd which is
commit 0ad529d9fd2bfa3fc619552a8d2fb2f2ef0bce2e upstream.

It does not build properly due to a previous revert for an Android
kernel abi break.  Bring this one back if it is needed in the future and
the abi is fixed up properly.

Bug: 161946584
Change-Id: Ia735e0ca4ae93bf663fb44fc745d1a232b41b47c
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

net/mptcp/protocol.c

@@ -2798,12 +2798,6 @@ static int mptcp_disconnect(struct sock *sk, int flags)
 	struct mptcp_subflow_context *subflow;
 	struct mptcp_sock *msk = mptcp_sk(sk);
 
-	/* Deny disconnect if other threads are blocked in sk_wait_event()
-	 * or inet_wait_for_connect().
-	 */
-	if (sk->sk_wait_pending)
-		return -EBUSY;
-
 	mptcp_do_flush_join_list(msk);
 
 	mptcp_for_each_subflow(msk, subflow) {
@@ -2842,7 +2836,6 @@ struct sock *mptcp_sk_clone(const struct sock *sk,
 		inet_sk(nsk)->pinet6 = mptcp_inet6_sk(nsk);
 #endif
 
-	nsk->sk_wait_pending = 0;
 	__mptcp_init_sock(nsk);
 
 	msk = mptcp_sk(nsk);