Change in coreboot[master]: soc/mediatek/mt8186: add early initialization for eMMC

[Rex-BC Chen (Code Review)]

Attention is currently required from: Rex-BC Chen.
Hello Hung-Te Lin, build bot (Jenkins),

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

https://review.coreboot.org/c/coreboot/+/59294

to look at the new patch set (#3).

Change subject: soc/mediatek/mt8186: add early initialization for eMMC
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soc/mediatek/mt8186: add early initialization for eMMC

Some eMMCs need 80+ms for CMD1 to complete. And the payload may need to
access eMMC in the very early stage (for example, depthcharge needs it
20ms after started) so we have to start initialization in coreboot.

TEST=boot kernel from eMMC ok
BUG=b:202871018

Signed-off-by: Rex-BC Chen 
Change-Id: I3bc06b1fc506b1d6f54f7f456117d22477a87e29
---
M src/mainboard/google/corsola/mainboard.c
M src/soc/mediatek/common/include/soc/msdc.h
M src/soc/mediatek/mt8186/msdc.c
3 files changed, 6 insertions(+), 3 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/94/59294/3