IB:usnic: Add UDP support to usnic_transport.[hc]

This patch provides API for rest of usNIC code to increment or decrement
socket's reference count. Auxiliary socket APIs are also provided.

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

diff --cc drivers/infiniband/hw/usnic/usnic_transport.c
Simple merge

diff --cc drivers/infiniband/hw/usnic/usnic_transport.h
Simple merge