Change in coreboot[master]: tpm: Refactor TPM Kconfig dimensions

[Jes Klinke (Code Review)]

Attention is currently required from: Stefan Ott, Felix Singer, Patrick Rudolph, Jonathan Zhang, Nick Vaccaro, Arthur Heymans, Andrey Petrov, Piotr Król, Nico Huber, Sean Rhodes, Michał Żygowski, Johnny Lin, Christian Walter, Werner Zeh, Alexander Couzens, Yu-Ping Wu, Tim Chu, Frans Hendriks, Tristan Corrick, Jeremy Soller, Angel Pons, Julius Werner, Michael Niewöhner, Tim Crawford, Maxim Polyakov, Tim Wawrzynczak.
Jes Klinke has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/63424 )

Change subject: tpm: Refactor TPM Kconfig dimensions
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Patch Set 5:

(2 comments)

Commit Message:

https://review.coreboot.org/c/coreboot/+/63424/comment/7ba9a090_39cd2a8c 
PS3, Line 22: LPC_TPM
> LPC_TPM can be SPI, too, when it's connected to via SPI / CS#2. […]

I have no familiarity with LPC at all.  If you say that the support enabled by this switch is really for memory mapped TPM of sorts, then I am open to calling this MEMORY_MAPPED_TPM or MM_TPM, or should it rather be MEMORY_MAPPED_LPC_TPM?  Now is a good time to make such a change, if you can tell me what best describes the driver that it controls.

https://review.coreboot.org/c/coreboot/+/63424/comment/81a204bd_1f1a46c1 
PS3, Line 18: // How the TPM chip is connected on the mainboard.
            : config CRB_TPM
            : config I2C_TPM
            : config SPI_TPM
            : config LPC_TPM (new)
            :
> "connected on the mainboard" <- why drop `MAINBOARD_HAS_` then?

Julius suggested in https://review.coreboot.org/c/coreboot/+/63285 that MAINBOARD_HAS_XXX vs. XXX Kconfig was a pattern used when the board declared what was available, and menuconfig options allowed the user to choose whether to compile support for the feature or not.  But for the TPM case, often there were no visible menu option for the "plain" XXX switch, so the pattern did not really apply.

Maybe I should just change the comment here into "TPM connection type support", or something like that.