[XS] Change in coreboot[main]: symbols: Add REGION() and REGION_END() macros

[Yu-Ping Wu (Code Review)]

Attention is currently required from: Julius Werner.

Yu-Ping Wu has posted comments on this change by Yu-Ping Wu. ( https://review.coreboot.org/c/coreboot/+/86115?usp=email )

Change subject: symbols: Add REGION() and REGION_END() macros
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Patch Set 2:

(1 comment)

Patchset:

PS2:
> I'm not really sure what this improves? What's wrong with the existing notation?

1. Writing `mmu_config_range(REGION(sram), REGION_SIZE(sram))` improves the readability (than `mmu_config_range(_sram, REGION_SIZE(sram))`), as the relationship between `_sram` and `sram` is unclear from the call.
2. Using `REGION(name)` makes it easier for (new) developers to find the actual region definition.
3. Variables starting with `_` look like private ones that shouldn't be exposed.