[M] Change in coreboot[main]: device: Add a helper function to add a downstream bus

[Arthur Heymans (Code Review)]

Attention is currently required from: Christian Walter, Jincheng Li, Johnny Lin, Lean Sheng Tan, Patrick Rudolph, Shuo Liu, Tim Chu.

Arthur Heymans has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/80210?usp=email )

Change subject: device: Add a helper function to add a downstream bus
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Patch Set 3:

(1 comment)

File src/device/device.c:

https://review.coreboot.org/c/coreboot/+/80210/comment/7c88c7c8_b8c4311b :
PS3, Line 136: the to be
> typo?

Nope that's actually valid English.