Remove "=======" symbols from the MUX buffer diagram. This is useful to
not mess with git conflict markers when resolving a conflict.
* QCS out buffer diagram
* head left to_xfer
* -------------> ----------> ----->
- * ==================================================
+ * --------------------------------------------------
* |...............|xxxxxxxxxxx|<<<<<
- * ==================================================
+ * --------------------------------------------------
* ^ ack-off ^ sent-off ^ off
*
* STREAM frame