IB/sa: Add ib_init_ah_from_path()

Add a call to initialize address handle attributes given a path record.
This is used by the CM, and would be useful for users of UD QPs.

Signed-off-by: Sean Hefty <sean.hefty@intel.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

diff --cc drivers/infiniband/core/sa_query.c
Simple merge

diff --cc include/rdma/ib_sa.h
Simple merge