Revert "ppp: Fix throttling bugs"

This reverts commit a6540f731d506d9e82444cf0020e716613d4c46c, as
requested by Alan:

  "... as it was wrong, the pty code is now fixed and the fact this
   isn't reverted is breaking pptp setups."

Requested-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/net/ppp_async.c

@@ -356,6 +356,7 @@ ppp_asynctty_receive(struct tty_struct *tty, const unsigned char *buf,
 	if (!skb_queue_empty(&ap->rqueue))
 		tasklet_schedule(&ap->tsk);
 	ap_put(ap);
+	tty_unthrottle(tty);
 }
 
 static void

drivers/net/ppp_synctty.c

@@ -397,6 +397,7 @@ ppp_sync_receive(struct tty_struct *tty, const unsigned char *buf,
 	if (!skb_queue_empty(&ap->rqueue))
 		tasklet_schedule(&ap->tsk);
 	sp_put(ap);
+	tty_unthrottle(tty);
 }
 
 static void