[PATCH] tty: export get_current_tty

24ec839c causes this:

WARNING: "get_current_tty" [drivers/s390/char/fs3270.ko] undefined!

Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

drivers/char/tty_io.c

@@ -3821,6 +3821,7 @@ struct tty_struct *get_current_tty(void)
 	barrier();
 	return tty;
 }
+EXPORT_SYMBOL_GPL(get_current_tty);
 
 /*
  * Initialize the console device. This is called *early*, so