Fix some stray non-UTF-8 characters used in some ASCII art tables
by converting them to plain ASCII '|' instead.
Reviewed-by: Stefan Weil <sw@weilnetz.de>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>