IB/hfi1: Revert egress pkey check enforcement

Current code has some serious flaws. Disarm the flag
pending an appropriate patch.

Fixes: 53526500 ("IB/hfi1: Permanently enable P_Key checking in HFI")
Cc: stable@vger.kernel.org
Reviewed-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Alex Estrin <alex.estrin@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>