[coreboot-gerrit] Patch merged into coreboot/master: nb/intel/sandybridge: Fix PEG disablement

the following patch was just integrated into master:
commit aad34cda4bc9c14ed10b00fe5da3f32233257913
Author: Patrick Rudolph 
Date:   Wed Oct 21 18:05:01 2015 +0200

nb/intel/sandybridge: Fix PEG disablement

Fix regression introduced by:
    3660c0fc658e4e20ef079f762dfc7ad05c83544c
    "northbridge/intel/sandybridge: Enable PEG clock-gating on demand"

Issue observed:
    GNU/Linux kernel crashes in earlyinit on systems without PEG devices.
    The crash occurs on every boot in different functions.
    There's no problem on systems with PEG enabled.

Test system:
     * Lenovo T530
     * Intel Core i5-3320M CPU
     * Fedora GNU/Linux 4.1
     * PEG disabled in devicetree

Problem description:
    Tests shows that modifing PEG chicken bit or device enable bits
    after setting BIOS_RESET_CPL causes random crashes in GNU/Linux.

Problem solution:
    Disable PEG devices before setting BIOS_RESET_CPL.

Final testing results:
    No more random kernel crashes.

Change-Id: I4a967c2d00d7d1e4426cf5abdd5f616c21557da7
    Signed-off-by: Patrick Rudolph 
    Reviewed-on: http://review.coreboot.org/12112
    Tested-by: build bot (Jenkins)
    Reviewed-by: Nico Huber

See http://review.coreboot.org/12112 for details.

-gerrit