tty: Bracket ldisc release with TTY_DEBUG_HANGUP messages

Expected typical log output:
[    2.437211] tty_open: opening pts1...
[    2.443376] tty_open: opening pts5...
[    2.447830] tty_release: ptm0 (tty count=1)...
[    2.447849] pts0 vhangup...
[    2.447865] tty_release: ptm0: final close
[    2.447876] tty_release: ptm0: freeing structure...
[    2.451634] tty_release: tty1 (tty count=1)...
[    2.451638] tty_release: tty1: final close
[    2.451654] tty_release: tty1: freeing structure...
[    2.452505] tty_release: pts5 (tty count=2)...
[    2.453029] tty_open: opening pts0...

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/tty_io.c

@@ -1836,7 +1836,7 @@ int tty_release(struct inode *inode, struct file *filp)
 		return 0;
 
 #ifdef TTY_DEBUG_HANGUP
-	printk(KERN_DEBUG "%s: freeing tty structure...\n", __func__);
+	printk(KERN_DEBUG "%s: %s: final close\n", __func__, tty_name(tty, buf));
 #endif
 	/*
 	 * Ask the line discipline code to release its structures
@@ -1848,6 +1848,9 @@ int tty_release(struct inode *inode, struct file *filp)
 	if (o_tty)
 		tty_flush_works(o_tty);
 
+#ifdef TTY_DEBUG_HANGUP
+	printk(KERN_DEBUG "%s: %s: freeing structure...\n", __func__, tty_name(tty, buf));
+#endif
 	/*
 	 * The release_tty function takes care of the details of clearing
 	 * the slots and preserving the termios structure. The tty_unlock_pair