i40e_main: mark expected switch fall-through

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

Addresses-Coverity-ID: 114790 ("Missing break in switch")
Signed-off-by: NGustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/intel/i40e/i40e_main.c

@@ -1800,6 +1800,7 @@ static void i40e_vsi_setup_queue_map(struct i40e_vsi *vsi,
 						       num_tc_qps);
 					break;
 				}
+				/* fall through */
 			case I40E_VSI_FDIR:
 			case I40E_VSI_SRIOV:
 			case I40E_VSI_VMDQ2: