use templates for TLCS900 I/O ports

[felipesanches]

Based on feedback from @cuavas at #12684 (comment), this PR uses templates to "avoid copy/pasta".

[felipesanches]

@cuavas, I consider this ready for review.

[felipesanches]

I noticed that it would, as usual, be problematic to declare the enum Ports outside of the device class, as that way it would be declared globally. And when I tried to declare it inside the tmp95c063_device class, it became uncomfortable to keep prepending "tmp95c061_device::" to all references to port names (like tmp95c061_device::PORT_A). Maybe I'm unaware of a better way of doing it, so I would appreciate if you have any suggestions.

One alternative approach that I pushed as a separate commit, so that it is easier to drop it if not considered good, was to use static constexpr uint8_t statements for the I/O port names, inside the cpu device classes (tmp95c061_device and tmp95c063_device). That works, but I am not sure what @cuavas thinks. Please let me know.

[cuavas]

That’s much neater, thanks.