IB/srp: Constify a function argument

This patch does not change any functionality.
Signed-off-by: NBart Van Assche <bart.vanassche@sandisk.com>
Cc: Sagi Grimberg <sagig@mellanox.com>
Cc: Sebastian Parschauer <sebastian.riemer@profitbricks.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

drivers/infiniband/ulp/srp/ib_srp.c

@@ -2172,7 +2172,7 @@ static uint32_t srp_compute_rq_tmo(struct ib_qp_attr *qp_attr, int attr_mask)
 }
 
 static void srp_cm_rep_handler(struct ib_cm_id *cm_id,
-			       struct srp_login_rsp *lrsp,
+			       const struct srp_login_rsp *lrsp,
 			       struct srp_rdma_ch *ch)
 {
 	struct srp_target_port *target = ch->target;