USB: cdc-acm: quirk for Conexant CX93010 USB modem

This patch gets my Rosewill RNX-56USB USB modem (with Conexant CX93010
chipset) up and running to the point where I can send AT commands and
retrieve caller ID data, which is all I want to do with it.

Signed-off-by: Eric Sandeen <sandeen@sandeen.net>
Acked-by: Oliver Neukum <oneukum@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>