tty: some ICANON magic is in the wrong places

Move the set up on ldisc change into the ldisc
Move the INQ/OUTQ cases into the driver not in shared ioctl code where it
gives bogus answers for other ldisc values

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/tty.h b/include/linux/tty.h
index 3c7c757..3b8121d 100644
--- a/include/linux/tty.h
+++ b/include/linux/tty.h
@@ -466,7 +466,7 @@
 #endif
 
 /* tty_ioctl.c */
-extern int n_tty_ioctl(struct tty_struct *tty, struct file *file,
+extern int n_tty_ioctl_helper(struct tty_struct *tty, struct file *file,
 		       unsigned int cmd, unsigned long arg);
 
 /* serial.c */