net: thunderx: mark expected switch fall-throughs in nicvf_main()

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

Cc: Sunil Goutham <sgoutham@cavium.com>
Cc: Robert Richter <rric@kernel.org>
Cc: linux-arm-kernel@lists.infradead.org
Cc: netdev@vger.kernel.org
Signed-off-by: NGustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/cavium/thunder/nicvf_main.c

@@ -565,8 +565,10 @@ static inline bool nicvf_xdp_rx(struct nicvf *nic, struct bpf_prog *prog,
 		return true;
 	default:
 		bpf_warn_invalid_xdp_action(action);
+		/* fall through */
 	case XDP_ABORTED:
 		trace_xdp_exception(nic->netdev, prog, action);
+		/* fall through */
 	case XDP_DROP:
 		/* Check if it's a recycled page, if not
 		 * unmap the DMA mapping.