TTY: use tty_port_register_device

Currently we have no way to assign tty->port while performing tty
installation. There are two ways to provide the link tty_struct =>
tty_port. Either by calling tty_port_install from tty->ops->install or
tty_port_register_device called instead of tty_register_device when
the device is being set up after connected.

In this patch we modify most of the drivers to do the latter. When the
drivers use tty_register_device and we have tty_port already, we
switch to tty_port_register_device. So we have the tty_struct =>
tty_port link for free for those.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/tty/ehv_bytechan.c b/drivers/tty/ehv_bytechan.c
index 4813684..4ab936b 100644
--- a/drivers/tty/ehv_bytechan.c
+++ b/drivers/tty/ehv_bytechan.c
@@ -738,16 +738,17 @@
 		goto error;
 	}
 
-	bc->dev = tty_register_device(ehv_bc_driver, i, &pdev->dev);
+	tty_port_init(&bc->port);
+	bc->port.ops = &ehv_bc_tty_port_ops;
+
+	bc->dev = tty_port_register_device(&bc->port, ehv_bc_driver, i,
+			&pdev->dev);
 	if (IS_ERR(bc->dev)) {
 		ret = PTR_ERR(bc->dev);
 		dev_err(&pdev->dev, "could not register tty (ret=%i)\n", ret);
 		goto error;
 	}
 
-	tty_port_init(&bc->port);
-	bc->port.ops = &ehv_bc_tty_port_ops;
-
 	dev_set_drvdata(&pdev->dev, bc);
 
 	dev_info(&pdev->dev, "registered /dev/%s%u for byte channel %u\n",