IB/usnic: Add Cisco VIC low-level hardware driver

This adds a driver that allows userspace to use UD-like QPs over a
proprietary Cisco transport with Cisco's Virtual Interface Cards (VICs),
including VIC 1240 and 1280 cards.

Signed-off-by: Upinder Malhi <umalhi@cisco.com>
Signed-off-by: Christian Benvenuti <benve@cisco.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>