net: ethernet: ti: cpts: mark expected switch fall-through

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

Addresses-Coverity-ID: 114813 ("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/ti/cpts.c

@@ -161,6 +161,7 @@ static int cpts_fifo_read(struct cpts *cpts, int match)
 				 */
 				break;
 			}
+			/* fall through */
 		case CPTS_EV_PUSH:
 		case CPTS_EV_RX:
 			list_del_init(&event->list);