[M] Change in coreboot[master]: mb/google/rex: Implement S0ix hooks aka `MS0X` method

[Sukumar Ghorai (Code Review)]

Attention is currently required from: Utkarsh H Patel, Subrata Banik, Kapil Porwal, Ivy Jian, Sridhar Siricilla, Eric Lai.

Sukumar Ghorai has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/70196 )

Change subject: mb/google/rex: Implement S0ix hooks aka `MS0X` method
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Patch Set 8:

(1 comment)

Patchset:

PS8: 
I do see slp_s0 toggle 1st S0is after boot. may stay high hence sub-sequent s0ix cycle does not toggle. need to prob the signals.

Success log (1st S0ix):
[139.985900 ACPI kbli[139.988800 KB Clear Buffer]
22-12-02 10:59:18.752 [140.223000 HI: power state 16 = S0S0ix, in 0x00df
22-12-02 10:59:18.990 C 0x00a9]
22-12-02 10:59:18.991 [140.288100 lid-accel: 0: init failed: 1]
22-12-02 10:59:19.056 [140.290I: power state 5 = S0ix, in 0x00df
22-12-02 10:59:19.061 700 tcs3400_init failed reading ID reg 0x92, ret=1]
22-12-02 10:59:19.067 [140.292500 PD:S0->S3]