isdn/gigaset/isocdata: mark expected switch fall-through

Notice that in this particular case, I replaced the
"--v-- fall through --v--" comment with a proper
"fall through", which is what GCC is expecting to
find.

This fix is part of the ongoing efforts to enabling
-Wimplicit-fallthrough
Signed-off-by: NGustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/isdn/gigaset/isocdata.c

@@ -906,7 +906,7 @@ static void cmd_loop(unsigned char *src, int numbytes, struct inbuf_t *inbuf)
 				cs->respdata[0] = 0;
 				break;
 			}
-			/* --v-- fall through --v-- */
+			/* fall through */
 		case '\r':
 			/* end of message line, pass to response handler */
 			if (cbytes >= MAX_RESP_SIZE) {