tty: add TIOCVHANGUP to allow clean tty shutdown of all ttys

This is useful for system management software so that it can kick
off things like gettys and everything that's started from a tty,
before we reuse it from/for something else or shut it down.

Without this ioctl it would have to temporarily become the owner of
the tty, then call vhangup() and then give it up again.

Cc: Lennart Poettering <lennart@poettering.net>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/arch/powerpc/include/asm/ioctls.h b/arch/powerpc/include/asm/ioctls.h
index c7dc17c..e9b7887 100644
--- a/arch/powerpc/include/asm/ioctls.h
+++ b/arch/powerpc/include/asm/ioctls.h
@@ -96,6 +96,7 @@
 #define TIOCSPTLCK	_IOW('T',0x31, int)  /* Lock/unlock Pty */
 #define TIOCGDEV	_IOR('T',0x32, unsigned int) /* Get primary device node of /dev/console */
 #define TIOCSIG		_IOW('T',0x36, int)  /* Generate signal on Pty slave */
+#define TIOCVHANGUP	0x5437
 
 #define TIOCSERCONFIG	0x5453
 #define TIOCSERGWILD	0x5454