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>
diff --git a/drivers/net/ppp_synctty.c b/drivers/net/ppp_synctty.c
index aa3d39f..d2fa2db 100644
--- a/drivers/net/ppp_synctty.c
+++ b/drivers/net/ppp_synctty.c
@@ -397,6 +397,7 @@
 	if (!skb_queue_empty(&ap->rqueue))
 		tasklet_schedule(&ap->tsk);
 	sp_put(ap);
+	tty_unthrottle(tty);
 }
 
 static void