[S] Change in coreboot[main]: drivers/option: Add CBFS file based option backend

[Nicholas Chin (Code Review)]

Nicholas Chin has uploaded a new patch set (#2). ( https://review.coreboot.org/c/coreboot/+/85905?usp=email )

Change subject: drivers/option: Add CBFS file based option backend
......................................................................

drivers/option: Add CBFS file based option backend

Add a new option backend that uses values stored in CBFS files, similar
to the SeaBIOS runtime config options stored in files with the etc/
prefix. Values can be set using `cbfstool coreboot.rom add-int -i value
-n option_name`.

Tested with QEMU Q35 by setting various options for "sata_mode" and
observing the console output for the SATA controller mode during
i82801ix_sata initialization.

Change-Id: Ifc0439ee42f13f49ae54d4855d1d9333c39b01f5
Signed-off-by: Nicholas Chin 
---
M src/Kconfig
M src/drivers/option/Makefile.mk
A src/drivers/option/cbfs_file_option.c
3 files changed, 33 insertions(+), 0 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/05/85905/2