net/mlx5e: Mark expected switch fall-throughs

In preparation to enabling -Wimplicit-fallthrough, mark switch cases
where we are expecting to fall through.

Addresses-Coverity-ID: 114808 ("Missing break in switch")
Addresses-Coverity-ID: 114802 ("Missing break in switch")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c

@@ -91,9 +91,11 @@ bool mlx5e_xdp_handle(struct mlx5e_rq *rq, struct mlx5e_dma_info *di,
 		return true;
 	default:
 		bpf_warn_invalid_xdp_action(act);
+		/* fall through */
 	case XDP_ABORTED:
 xdp_abort:
 		trace_xdp_exception(rq->netdev, prog, act);
+		/* fall through */
 	case XDP_DROP:
 		rq->stats->xdp_drop++;
 		return true;