IB/mlx5: Fix missing congestion control debugfs on rep rdma device

Cited commit missed to include low level congestion control related
debugfs stage initialization.  This resulted in missing debugfs entries
for cc_params of a RDMA device.

Add them back.

Fixes: b5ca15ad7e ("IB/mlx5: Add proper representors support")
Link: https://lore.kernel.org/r/20200227125407.99803-1-leon@kernel.org
Signed-off-by: Parav Pandit <parav@mellanox.com>
Reviewed-by: Mark Bloch <markb@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/hw/mlx5/main.c

@@ -7078,6 +7078,9 @@ const struct mlx5_ib_profile raw_eth_profile = {
 	STAGE_CREATE(MLX5_IB_STAGE_COUNTERS,
 		     mlx5_ib_stage_counters_init,
 		     mlx5_ib_stage_counters_cleanup),
+	STAGE_CREATE(MLX5_IB_STAGE_CONG_DEBUGFS,
+		     mlx5_ib_stage_cong_debugfs_init,
+		     mlx5_ib_stage_cong_debugfs_cleanup),
 	STAGE_CREATE(MLX5_IB_STAGE_UAR,
 		     mlx5_ib_stage_uar_init,
 		     mlx5_ib_stage_uar_cleanup),