IB/sa: Add new QoS fields to path record

The QoS annex defines new fields for path records.  Add them to the
ib_sa for consumers that want to use them.

Signed-off-by: Sean Hefty <sean.hefty@intel.com>
Reviewed-by: Or Gerlitz <ogerlitz@voltaire.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>