[S] Change in coreboot[main]: northbridge/intel/sandybridge: Enable x86_64 for mrc.bin

[Patrick Rudolph (Code Review)]

Attention is currently required from: Angel Pons, Arthur Heymans, Patrick Rudolph.

Hello Angel Pons, Arthur Heymans, build bot (Jenkins),

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

https://review.coreboot.org/c/coreboot/+/79754?usp=email

to look at the new patch set (#3).

The following approvals got outdated and were removed:
Code-Review+2 by Arthur Heymans

Change subject: northbridge/intel/sandybridge: Enable x86_64 for mrc.bin
......................................................................

northbridge/intel/sandybridge: Enable x86_64 for mrc.bin

Enable x86_64 support for MRC.bin:
- Add a wrapper function for console printing that calls into
  long mode to call native do_putchar
- Remove Kconfig guard for x86_64 when MRC is being used

Tested: Booted Lenovo X220 using mrc.bin under x86_64 and
        MRC is able to print to the console.

Change-Id: I21ffcb5f5d4bf155593e8111531bdf0ed7071dfc
Signed-off-by: Patrick Rudolph 
---
M src/cpu/intel/model_206ax/Kconfig
M src/northbridge/intel/sandybridge/mrc_wrapper.S
M src/northbridge/intel/sandybridge/raminit_mrc.c
3 files changed, 20 insertions(+), 3 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/54/79754/3