IB/hfi1: Stricter bounds checking of MAD trap index

The macro size is valid. This change makes it less ambiguous.
Bounds check trap type for better security.

Reviewed-by: Michael J. Ruhl <michael.j.ruhl@intel.com>
Signed-off-by: Kamenee Arumugam <kamenee.arumugam@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>