Driver core: convert tty core to use struct device

Converts from using struct "class_device" to "struct device" making
everything show up properly in /sys/devices/ with symlinks from the
/sys/class directory.

Also fixes up the isdn drivers that were putting something in the class
device's directory.

Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/isdn/gigaset/interface.c b/drivers/isdn/gigaset/interface.c
index 596f3ae..7edea01 100644
--- a/drivers/isdn/gigaset/interface.c
+++ b/drivers/isdn/gigaset/interface.c
@@ -625,13 +625,13 @@
 		return;
 
 	tasklet_init(&cs->if_wake_tasklet, &if_wake, (unsigned long) cs);
-	cs->class = tty_register_device(drv->tty, cs->minor_index, NULL);
+	cs->tty_dev = tty_register_device(drv->tty, cs->minor_index, NULL);
 
-	if (!IS_ERR(cs->class))
-		class_set_devdata(cs->class, cs);
+	if (!IS_ERR(cs->tty_dev))
+		dev_set_drvdata(cs->tty_dev, cs);
 	else {
 		warn("could not register device to the tty subsystem");
-		cs->class = NULL;
+		cs->tty_dev = NULL;
 	}
 }
 
@@ -645,7 +645,7 @@
 
 	tasklet_disable(&cs->if_wake_tasklet);
 	tasklet_kill(&cs->if_wake_tasklet);
-	cs->class = NULL;
+	cs->tty_dev = NULL;
 	tty_unregister_device(drv->tty, cs->minor_index);
 }