net/core/skmsg: Replace call_rcu_sched() with call_rcu()

Now that call_rcu()'s callback is not invoked until after all
preempt-disable regions of code have completed (in addition to explicitly
marked RCU read-side critical sections), call_rcu() can be used in place
of call_rcu_sched().  This commit therefore makes that change.
Signed-off-by: NPaul E. McKenney <paulmck@linux.ibm.com>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: <netdev@vger.kernel.org>

net/core/skmsg.c

@@ -580,7 +580,7 @@ void sk_psock_drop(struct sock *sk, struct sk_psock *psock)
 	write_unlock_bh(&sk->sk_callback_lock);
 	sk_psock_clear_state(psock, SK_PSOCK_TX_ENABLED);
 
-	call_rcu_sched(&psock->rcu, sk_psock_destroy);
+	call_rcu(&psock->rcu, sk_psock_destroy);
 }
 EXPORT_SYMBOL_GPL(sk_psock_drop);