staging: typec: tcpci: mark expected switch fall-through in tcpci_to_typec_cc

In preparation to enabling -Wimplicit-fallthrough, mark switch cases
where we are expecting to fall through.
Signed-off-by: NGustavo A. R. Silva <garsilva@embeddedor.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/typec/tcpci.c

@@ -139,6 +139,7 @@ static enum typec_cc_status tcpci_to_typec_cc(unsigned int cc, bool sink)
 	case 0x3:
 		if (sink)
 			return TYPEC_CC_RP_3_0;
+		/* fall through */
 	case 0x0:
 	default:
 		return TYPEC_CC_OPEN;