Change in coreboot[master]: soc/mediatek/mt8192: adjust i2c "tLOW" and "tSU,STO"

[Jg Daolongzhu (Code Review)]

Attention is currently required from: Jg Daolongzhu, Xi Chen.
Hello Xi Chen, Hung-Te Lin, build bot (Jenkins), Yu-Ping Wu,

I'd like you to reexamine a change. Please visit

https://review.coreboot.org/c/coreboot/+/51024

to look at the new patch set (#14).

Change subject: soc/mediatek/mt8192: adjust i2c "tLOW" and "tSU,STO"
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soc/mediatek/mt8192: adjust i2c "tLOW" and "tSU,STO"

The i2c actiming with the default reg setting cannot meet spec,
so we need to set some regs.
1. adjust the ratio of SCL high and low level, to adjust "tLOW".
2. modify ext_conf reg to adjust "tSU,STO".

BUG=b:179000159
TEST=Test on asurada (MT8192), boot pass,
timing pass.

Signed-off-by: Daolong Zhu 
Change-Id: Ifbe97edbc38972af5b782fb93342ee0616127dd8
---
M src/soc/mediatek/mt8192/i2c.c
1 file changed, 29 insertions(+), 3 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/24/51024/14