[XL] Change in coreboot[main]: [wip C11 to C23] use nullptr & nullptr_t

[Eric Lai (Code Review)]

Attention is currently required from: Alexander Couzens, Andrey Petrov, Arthur Heymans, Caveh Jalali, Christian Walter, Cliff Huang, Dinesh Gehlot, Elyes Haouas, Eran Mitrani, Erik van den Bogaert, Evgeny Zinoviev, Felix Held, Forest Mittelberg, Frans Hendriks, Fred Reitberger, Hung-Te Lin, Jakub Czapiga, Jason Glenesk, Jason Nien, Jeff Daly, Jeremy Soller, Johnny Lin, Jonathan Zhang, Jonathon Hall, Julius Werner, Jérémy Compostella, Kapil Porwal, Lance Zhao, Lean Sheng Tan, Martin L Roth, Martin Roth, Matt DeVillier, Michał Żygowski, Morgan Jang, Nicholas Chin, Nick Vaccaro, Patrick Rudolph, Philipp Hug, Piotr Król, Ron Minnich, Ronak Kanabar, Sean Rhodes, Shuo Liu, Subrata Banik, Sumeet R Pawnikar, Tarun, Tim Chu, Tim Crawford, Tim Wawrzynczak, Vanessa Eusebio, Varshit Pandya, Werner Zeh, Xi Chen, Yidi Lin, Yu-Ping Wu.

Eric Lai has posted comments on this change by Elyes Haouas. ( https://review.coreboot.org/c/coreboot/+/83585?usp=email )

Change subject: [wip C11 to C23] use nullptr & nullptr_t
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Patch Set 1:

(1 comment)

Patchset:

PS1: 
Could you help tear down the change, too many to check one by one.