IB/hfi1, qib: Add ieth to the packet header definitions

A new union member "ieth" (Invalidate Extended Transport Header) is
added to the packet header definition in preparation of supporting
the send with invalidate opcode.

Reviewed-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Reviewed-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Jianxin Xiong <jianxin.xiong@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>