net/fungible: Add service module for Fungible drivers

Fungible cards have a number of different PCI functions and thus
different drivers, all of which use a common method to initialize and
interact with the device. This commit adds a library module that
collects these common mechanisms. They mainly deal with device
initialization, setting up and destroying queues, and operating an admin
queue. A subset of the FW interface is also included here.

Signed-off-by: Dimitris Michailidis <dmichail@fungible.com>
Signed-off-by: David S. Miller <davem@davemloft.net>