Input: atmel_mxt_ts - 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: Dmitry Torokhov <dmitry.torokhov@gmail.com>

drivers/input/touchscreen/atmel_mxt_ts.c

@@ -488,7 +488,7 @@ static int mxt_lookup_bootloader_address(struct mxt_data *data, bool retry)
 			bootloader = appmode - 0x24;
 			break;
 		}
-		/* Fall through for normal case */
+		/* Fall through - for normal case */
 	case 0x4c:
 	case 0x4d:
 	case 0x5a: