gigaset: asyncdata: mark expected switch fall-throughs

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

Addresses-Coverity-ID: 1364476 ("Missing break in switch")
Addresses-Coverity-ID: 1364477 ("Missing break in switch")
Signed-off-by: NGustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/isdn/gigaset/asyncdata.c

@@ -65,7 +65,7 @@ static unsigned cmd_loop(unsigned 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) {
@@ -100,7 +100,7 @@ static unsigned cmd_loop(unsigned numbytes, struct inbuf_t *inbuf)
 				goto exit;
 			}
 			/* quoted or not in DLE mode: treat as regular data */
-			/* --v-- fall through --v-- */
+			/* fall through */
 		default:
 			/* append to line buffer if possible */
 			if (cbytes < MAX_RESP_SIZE)