[M] Change in coreboot[main]: google/*: Clean up Kconfg board selection for Google MTK boards

[Yu-Ping Wu (Code Review)]

Attention is currently required from: Felix Singer, Hung-Te Lin, Julius Werner, Yidi Lin.

Yu-Ping Wu has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/79063?usp=email )

Change subject: google/*: Clean up Kconfg board selection for Google MTK boards
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Patch Set 1:

(5 comments)

File src/mainboard/google/corsola/Kconfig:

https://review.coreboot.org/c/coreboot/+/79063/comment/3e408669_a096bd24 :
PS1, Line 22: 	select DRIVER_ANALOGIX_ANX7625 if BOARD_GOOGLE_CHINCHOU
In the past we've changed the file multiple times in order to better organize these display driver Kconfigs. Note that only one driver should be selected, except on Steelix where old revisions use a different eDP bridge. The best option we have so far is to let each board select the right config, so that it's clear that only one of them is selected.

Now if the preferred model is to hide `BOARD_GOOGLE_*` from the Kconfig file, I think we'll want to change how these drivers are selected. In particular, we'll need to make sure both options are mutually exclusive (except for Steelix). My suggestion would be:

```
config CORSOLA_HAS_MIPI_PANEL
    def_bool BOARD_GOOGLE_STARYU_COMMON
config DRIVER_ANALOGIX_ANX7625
    def_bool BOARD_GOOGLE_KINGLER_COMMON || BOARD_GOOGLE_CHINCHOU || ...
    depends on !CORSOLA_HAS_MIPI_PANEL
config DRIVER_PARADE_PS8640
    def_bool !DRIVER_ANALOGIX_ANX7625 || BOARD_GOOGLE_STEELIX
    depends on !CORSOLA_HAS_MIPI_PANEL
```

Do you think that's cleaner than the current patch?

File src/mainboard/google/geralt/Kconfig:

https://review.coreboot.org/c/coreboot/+/79063/comment/106057be_7b8ed6b8 :
PS1, Line 5: 	def_bool BOARD_GOOGLE_GERALT
And `BOARD_GOOGLE_CIRI` (added by a recent patch CB:78954).

https://review.coreboot.org/c/coreboot/+/79063/comment/f7ca0d8f_08f54390 :
PS1, Line 62: SDCARD_INIT
Also modify this for consistency (need to rebase).

File src/mainboard/google/kukui/Kconfig:

https://review.coreboot.org/c/coreboot/+/79063/comment/213d8053_35485f20 :
PS1, Line 27: 		 BOARD_GOOGLE_WILLOW
This needs to select `BOARD_GOOGLE_KUKUI_COMMON`. Here kukui is considered as the parent of jacuzzi.

https://review.coreboot.org/c/coreboot/+/79063/comment/8228d956_63e9ae5f :
PS1, Line 36: 	select VBOOT_VBNV_FLASH
Not related to the patch, but I've always been wondering how repeated definitions of a Kconfig option work. Is this line equivalent to `select VBOOT_VBNV_FLASH if VBOOT` in `BOARD_SPECIFIC_OPTIONS`?