orinoco_usb: mark expected switch fall-through

In preparation to enabling -Wimplicit-fallthrough, mark switch cases
where we are expecting to fall through.
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/intersil/orinoco/orinoco_usb.c

@@ -908,6 +908,7 @@ static int ezusb_access_ltv(struct ezusb_priv *upriv,
 	case EZUSB_CTX_REQ_SUBMITTED:
 		if (!ctx->in_rid)
 			break;
+		/* fall through */
 	default:
 		err("%s: Unexpected context state %d", __func__,
 		    state);