[S] Change in coreboot[main]: mb/google/nissa: Add system type selection for Chromebox devices

[Subrata Banik (Code Review)]

Attention is currently required from: David Wu, Derek Huang, Dinesh Gehlot, Eric Lai, Ivy Jian, Jayvik Desai, Kapil Porwal, Nick Vaccaro.

Subrata Banik has posted comments on this change by Ivy Jian. ( https://review.coreboot.org/c/coreboot/+/86392?usp=email )

Change subject: mb/google/nissa: Add system type selection for Chromebox devices
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Patch Set 1:

(1 comment)

File src/mainboard/google/brya/Kconfig:

https://review.coreboot.org/c/coreboot/+/86392/comment/f37c3b92_913ba392?usp... :
PS1, Line 720: config SYSTEM_TYPE_CHROMEBOX
can you please add src/Kconfig +655

```
config SYSTEM_TYPE_BOX
   default n
   bool
   help
     For devices like chromebox, mac-mini etc. These devices without built-in display and operates on AC supply alone
```

then make sure SYSTEM_TYPE_BOX is selected by BOARD_GOOGLE_DIRKS and other should select SYSTEM_TYPE_LAPTOP