[XS] Change in coreboot[main]: soc/mediatek/common: Fix eMMC clock

[Hung-Te Lin (Code Review)]

Attention is currently required from: Kiwi Liu, Mengqi Zhang, Paul Menzel, Yu-Ping Wu.

Hung-Te Lin has posted comments on this change by Kiwi Liu. ( https://review.coreboot.org/c/coreboot/+/84298?usp=email )

Change subject: soc/mediatek/common: Fix eMMC clock
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Patch Set 9:

(1 comment)

File src/soc/mediatek/common/msdc.c:

https://review.coreboot.org/c/coreboot/+/84298/comment/86c2445f_6d639ede?usp... :
PS9, Line 432: 	host->src_hz = 400 * 1000 * 1000;
> Are you sure you tested this patch? How would the frequency be under 400 kHz with this patch?

I think the description does not have enough details, but the 400k was actually set in line 447 `SET_CLOCK(mmc_ctrlr, 400 * 1000);`. The 400M here is set for src_hz, that will be divided when setting clock, so it's definitely much larger than 400K.

However I also don't have enough knowledge to figure out why changing this from 50 to 400 would solve the problem. Also we really need to know if this will impact system boot time.