drivers/staging/tty/specialix.c: convert func_enter to func_exit

Convert calls to func_enter on leaving a function to func_exit.

The semantic patch that fixes this problem is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@@
@@

- func_enter();
+ func_exit();
  return...;
// </smpl>

Signed-off-by: Julia Lawall <julia@diku.dk>
Cc: Roger Wolff <R.E.Wolff@BitWizard.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>