tty: introduce and use tty_port_tty_vhangup() helper

tty: introduce and use tty_port_tty_vhangup() helper

This code (tty_get -> vhangup -> tty_put) is repeated on few places.
Introduce a helper similar to tty_port_tty_hangup() (asynchronous) to
handle even vhangup (synchronous).

And use it on those places.

In fact, reuse the tty_port_tty_hangup()'s code and call tty_vhangup()
depending on a new bool parameter.

Signed-off-by: "Jiri Slaby (SUSE)" <jirislaby@kernel.org>
Cc: Karsten Keil <isdn@linux-pingi.de>
Cc: David Lin <dtwlin@gmail.com>
Cc: Johan Hovold <johan@kernel.org>
Cc: Alex Elder <elder@kernel.org>
Cc: Oliver Neukum <oneukum@suse.com>
Cc: Marcel Holtmann <marcel@holtmann.org>
Cc: Johan Hedberg <johan.hedberg@gmail.com>
Cc: Luiz Augusto von Dentz <luiz.dentz@gmail.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20250611100319.186924-2-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>