[PATCH] USB: ftdi_sio: Adds support for iPlus device.

Adds support in ftdi_sio usbserial driver for USB modems sold by
Plus GSM Company in Poland.

Signed-off-by: Luiz Fernando Capitulino <lcapitulino@mandriva.com.br>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>