staging/rdma/hfi1: Fix SL->SC checks

SLs which are mapped to SC15 are invalid and should fail the
operation.

For RC/UC QP types, verify the AH information at modify_qp time and
fail the modify_qp if the SL is invalid.

For other QP types check the SL during post_send via the new rdmavt
callback.

Reviewed-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Reviewed-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>