[S] Change in coreboot[main]: soc/intel/cmn/pmc: Add support for early power off

[Subrata Banik (Code Review)]

Attention is currently required from: Intel coreboot Reviewers, Julius Werner, Jérémy Compostella, Karthik Ramasubramanian.

Subrata Banik has posted comments on this change by Subrata Banik. ( https://review.coreboot.org/c/coreboot/+/86336?usp=email )

Change subject: soc/intel/cmn/pmc: Add support for early power off
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Patch Set 3:

(1 comment)

Patchset:

PS3: 
Please hold review in this CL as I will refactor this CL

1. keep only __weak here

```
/* Perform platform specific override to add support for early power off */
__weak void platform_do_early_poweroff(void)
{
    printk(BIOS_EMERG, "This platform doesn't know how to power off before ramstage,"
    " hanging!\n");
    	halt();
}
```

2. Implement the override within the respective SoC reset.c file. This will allow us to get rid of the generic overrides (if any) when Intel implements the early shutdown feature in the future (WCL) SoC.

for now, I will implement the override for RPL and PTL inside their reset.c file