new tlcs900 variant: TMP94C241

[felipesanches]

Used on the KN5000 driver.

[felipesanches]

Before/after comparison

On current git master, the screen gets almost completely black with just a glitch of half a dozen colored pixels at the top line:

With the new CPU variant implemented in this PR, we get a good-looking system message regarding control-panel MCU communications error:

[felipesanches]

This PR is a followup to previous work done at #12684. I believe that I have already addressed all issues pointed out by @cuavas in his previous code review. In this PR I have included only the implementation of the new CPU variant and the small snippets of code in the KN5000 driver that use features on this variant.

The rest of the code for the kn5000 driver will be submitted as separate PRs later to make it easier to review and merge smaller chunks of code.

@wilbertpol and/or @ajrhacker, as you both are listed as authors of other variants of the TLCS900 family, could you please take a look at this PR?

[felipesanches]

Note: The wording of the ** ERROR in CPU data transmission ** message is a bit misleading. I know it is related to the control panel MCUs due to this description in the service manual:

[felipesanches]

To make that work, I'll need to implement UART support in the TMP94C241 CPU device and then use it to attach the MCUs (with HLE initially). But I'd like to land this PR before attempting that, as the amount of code needing review keeps growing.