IB/cm: Update protocol to support XRC

Update the REQ and REP messages to support XRC connection setup
according to the XRC Annex.  Several existing fields must be set to 0 or
1 when connecting XRC QPs, and a reserved field is changed to an
extended transport type.

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