Change in coreboot[master]: [WIP]drivers/efi: Add UEFI variable store option support

[Patrick Rudolph (Code Review)]

Attention is currently required from: Martin Roth - Personal, Patrick Rudolph.
Hello build bot (Jenkins), Martin Roth - Personal, Patrick Rudolph,

I'd like you to reexamine a change. Please visit

https://review.coreboot.org/c/coreboot/+/52564

to look at the new patch set (#2).

Change subject: [WIP]drivers/efi: Add UEFI variable store option support
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[WIP]drivers/efi: Add UEFI variable store option support

Add a driver to read UEFI variables stored in the SMMSTORE region.
This is particullary useful for EDK2 as payload and allows to reuse existing
tools to set/get options used by the firmware.

Test: Could enumerate all existing variables.

Change-Id: I8079f71d29da5dc2db956fc68bef1486fe3906bb
Signed-off-by: Patrick Rudolph 
---
M src/Kconfig
M src/commonlib/bsd/include/commonlib/bsd/cb_err.h
A src/drivers/efi/Kconfig
A src/drivers/efi/Makefile.inc
A src/drivers/efi/efi.c
A src/drivers/efi/efi.h
A src/drivers/efi/option.c
M src/drivers/smmstore/Makefile.inc
M src/drivers/smmstore/store.c
M src/include/smmstore.h
M src/vendorcode/intel/Makefile.inc
A src/vendorcode/intel/edk2/UDK2017/MdeModulePkg/Include/Guid/VariableFormat.h
A src/vendorcode/intel/edk2/option/option.h
13 files changed, 727 insertions(+), 9 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/64/52564/2