IB/ehca: QP code restructuring in preparation for SRQ

- Replace init_qp_queues() by a shorter init_qp_queue(), eliminating
  duplicate code.

- hipz_h_alloc_resource_qp() doesn't need a pointer to struct ehca_qp any
  longer. All input and output data is transferred through the parms
  parameter.

- Change the interface to also support SRQ.

Signed-off-by: Joachim Fenkes <fenkes@de.ibm.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>