Change in coreboot[master]: soc/intel/common: Add IOE P2SB for TCSS

[Subrata Banik (Code Review)]

Attention is currently required from: Ravishankar Sarawadi, John Zhao, Tim Wawrzynczak, Angel Pons, Patrick Rudolph, EricR Lai.
Subrata Banik has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/62721 )

Change subject: soc/intel/common: Add IOE P2SB for TCSS
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Patch Set 3:

(1 comment)

File src/soc/intel/common/block/include/intelblocks/p2sb.h:

https://review.coreboot.org/c/coreboot/+/62721/comment/5eee9488_857a43e5 
PS3, Line 33: uint32_t ioe_p2sb_sbi_read(uint8_t pid, uint16_t reg);
can I request you to add a help comment section here with details about `arguments`.

Initially I thought, `pid` is just IOE PID but later realised that, `pid` for end point device like TCSS etc.