Add support for multiple Contact DIO-16 cards for multiple I/O chassis
The PEMMID front-ends have two I/O chassis. These are V4 chassis with Contec DIO-16 adapters. showcards only shows one of them, but lspci -vn | grep 1221 shows both of them
This change may also need to be added to allow for multiple LIGO Timing Adapters, again from two I/O chassis