ipack: ipoctal: fix module reference leak

ipack: ipoctal: fix module reference leak

commit bb8a4fcb2136508224c596a7e665bdba1d7c3c27 upstream.

A reference to the carrier module was taken on every open but was only
released once when the final reference to the tty struct was dropped.

Fix this by taking the module reference and initialising the tty driver
data when installing the tty.

Fixes: 82a82340bab6 ("ipoctal: get carrier driver to avoid rmmod")
Cc: stable@vger.kernel.org      # 3.18
Cc: Federico Vaga <federico.vaga@cern.ch>
Acked-by: Samuel Iglesias Gonsalvez <siglesias@igalia.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://lore.kernel.org/r/20210917114622.5412-6-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>