Change in coreboot[master]: soc/mediatek/mt8186: Add a stub implementation of the MT8186 SoC

[Paul Menzel (Code Review)]

Attention is currently required from: Hung-Te Lin, Rex-BC Chen, Felix Held.
Paul Menzel has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/58640 )

Change subject: soc/mediatek/mt8186: Add a stub implementation of the MT8186 SoC
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Patch Set 2:

(3 comments)

Commit Message:

https://review.coreboot.org/c/coreboot/+/58640/comment/37d44b0c_22a4da4a 
PS2, Line 10:
> this doesn't look like a copy of the previous soc's directory, so i don't think that the questions a […]

Indeed. Currently we have MT8173, MT8183, MT8192 and MT8195. How does the new chip fit in there? What differences are there that the support cannot be integrated into existing code?

Also please mention the datasheet name and revision in the commit message.

https://review.coreboot.org/c/coreboot/+/58640/comment/5ced09f5_b3d5ad44 
PS2, Line 11: TEST=boot from SPI-NOR and show uart log
Tested on what board?

File src/soc/mediatek/mt8186/include/soc/timer.h:

PS2: 
This is the same as `mt8195/include/soc/timer.h` for example.