[XS] Change in coreboot[main]: mb/google/rex/var/deku: Enable RTD3 for SSD

[Curtis Chen (Code Review)]

Attention is currently required from: Curtis Chen, Dinesh Gehlot, Eran Mitrani, Jakub Czapiga, Kapil Porwal, Tarun.

Hello Dinesh Gehlot, Eran Mitrani, Jakub Czapiga, Kapil Porwal, Subrata Banik, Tarun, build bot (Jenkins),

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

https://review.coreboot.org/c/coreboot/+/84452?usp=email

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

Change subject: mb/google/rex/var/deku: Enable RTD3 for SSD
......................................................................

mb/google/rex/var/deku: Enable RTD3 for SSD

Deku S0ix is blocked by SSD. Enable RTD3 for SSD to unblock S0ix.

BUG=361011799
TEST=Deku can enter into S0iX.

suspend_stress_test w/o this CL (with Phison SSD)
```
Suspend failed, s0ix count did not increment from 19182060
Substate   Residency
S0i2.0     0
S0i2.1     0
S0i2.2     0
And PC10 residency is only 60% (by SoCWatch)
```

suspend_stress_test w/ this CL (with Phison SSD)
```
Substate   Residency
S0i2.0     0
S0i2.1     19186
S0i2.2     3389654
And PC10 residency is ~90% (by SoCWatch)

Change-Id: Iaded43a84ad1e245106d36a9d4aa83c40b046649
Signed-off-by: Curtis Chen 
---
M src/mainboard/google/rex/variants/deku/overridetree.cb
1 file changed, 7 insertions(+), 0 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/52/84452/2