[L] Change in coreboot[main]: mb/google/fatcat: Add override tree

[Cliff Huang (Code Review)]

Attention is currently required from: Jérémy Compostella, Pranava Y N.

Cliff Huang has posted comments on this change by Jérémy Compostella. ( https://review.coreboot.org/c/coreboot/+/84407?usp=email )

Change subject: mb/google/fatcat: Add override tree
......................................................................

Patch Set 1:

(2 comments)

File src/mainboard/google/fatcat/variants/fatcat/overridetree.cb:

https://review.coreboot.org/c/coreboot/+/84407/comment/7ed829f1_fc09ef30?usp... :
PS1, Line 79: 	[PchSerialIoIndexI2C4]  = PchSerialIoPci,
> Disable these as I2C0 and I2C4 are not used?

I2C4 is used for Touchscreen.

https://review.coreboot.org/c/coreboot/+/84407/comment/95668499_87a23245?usp... :
PS1, Line 157: device ref thc0 on end
> Please confirm if we are using this

This will be used for touchscreen with THC-i2c or THC-spi mode. In addition, this is function 0. we will need to enable thc0 when thc1 (function 1) is enabled.