Change in coreboot[master]: soc/intel/common/block/acpi: Add LPM requirements support to PEPD _DSM

[Cliff Huang (Code Review)]

Attention is currently required from: Furquan Shaikh, Tim Wawrzynczak, Angel Pons, Michael Niewöhner, Patrick Rudolph, Karthik Ramasubramanian.
Cliff Huang has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/56005 )

Change subject: soc/intel/common/block/acpi: Add LPM requirements support to PEPD _DSM
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Patch Set 2:

(1 comment)

File src/soc/intel/common/block/acpi/pep.c:

https://review.coreboot.org/c/coreboot/+/56005/comment/909a4c1e_ecf92a88 
PS2, Line 142: static void pep_s0ix_collect_lpm_requirements(void *unused)
Can we have separate functions: one to read out register value to a buffer and returns status and other one does acpigen_write_return_byte_buffer(). The first function will be called prior to acpigen_dsm_uuid_arr() so that we can have the enum_functions() check the status and decide to write 0x03 for the return value, or 0x00 in case error during IPC interface read?