Change in coreboot[master]: mb/google/dedede/var/magolor: Set core display clock to 172.8 MHz

[Ren Kuo (Code Review)]

Attention is currently required from: Henry Sun, Ren Kuo, Paul Menzel, Simon Yang, Kane Chen, Karthik Ramasubramanian.
Hello build bot (Jenkins), Henry Sun, Angel Pons, Simon Yang, Kane Chen, Karthik Ramasubramanian,

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

https://review.coreboot.org/c/coreboot/+/60301

to look at the new patch set (#8).

Change subject: mb/google/dedede/var/magolor: Set core display clock to 172.8 MHz
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mb/google/dedede/var/magolor: Set core display clock to 172.8 MHz

When using the default initial core display clock frequency, Magolor has
a rare stability issue where the startup of Chrome OS in secure mode may
hang. Slowing the initial core display clock frequency down to 172.8 MHz
as per Intel recommendation avoids this problem.

Depend on CL: https://review.coreboot.org/c/coreboot/+/60009
The CdClock=0xff is set in dedede baseboard,and we overwrite it as 0x0
(172.8 MHz) for magolor.

BUG=b:206557434
BRANCH=dedede
TEST=Build firmware and verify on fail DUTs.
     Check the DUTs can boot up in secure mode well.

Change-Id: I5a0ad2bed79b37775184f0bd0a0ef024900cbe34
Signed-off-by: Ren Kuo 
---
M src/mainboard/google/dedede/variants/magolor/overridetree.cb
1 file changed, 3 insertions(+), 0 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/01/60301/8