net/mlx5e: use indirect calls wrapper for the rx packet handler

We can avoid another indirect call per packet wrapping the rx
handler call with the proper helper.

To ensure that even the last listed direct call experience
measurable gain, despite the additional conditionals we must
traverse before reaching it, I tested reversing the order of the
listed options, with performance differences below noise level.

Together with the previous indirect call patch, this gives
~6% performance improvement in raw UDP tput.

v2 -> v3:
 - use only the direct calls always available regardless of
   the mlx5 build options
 - drop the direct call list macro, to keep the code as simple
   as possible for future rework

v1 -> v2:
 - update the direct call list and use a macro to define it,
   as per Saeed suggestion. An intermediated additional
   macro is needed to allow arg list expansion

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Acked-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlx5/core/en_rx.c

@@ -1333,7 +1333,8 @@ int mlx5e_poll_rx_cq(struct mlx5e_cq *cq, int budget)
 
 		mlx5_cqwq_pop(cqwq);
 
-		rq->handle_rx_cqe(rq, cqe);
+		INDIRECT_CALL_2(rq->handle_rx_cqe, mlx5e_handle_rx_cqe_mpwrq,
+				mlx5e_handle_rx_cqe, rq, cqe);
 	} while ((++work_done < budget) && (cqe = mlx5_cqwq_get_cqe(cqwq)));
 
 out: