[L] Change in coreboot[main]: soc/mediatek/mt8196: Add clk_buf drivers

[ot_song fan (Code Review)]

Attention is currently required from: Hung-Te Lin, Jarried Lin, Yidi Lin.

ot_song fan has uploaded a new patch set (#6) to the change originally created by Jarried Lin. ( https://review.coreboot.org/c/coreboot/+/85841?usp=email )

Change subject: soc/mediatek/mt8196: Add clk_buf drivers
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soc/mediatek/mt8196: Add clk_buf drivers

MT8196 uses MT6685 clk_buf, and will use new RC mode with srclken_rc.
The clk_buf will provide several 26M clocks, and these clocks can be
independently turned on. RC mode will determine which clocks to be
turned on based on users' requests, which is collected into PMRC_EN
register by srclken_rc.

TEST=Build pass.
BUG=b:317009620

Signed-off-by: ot_song fan 
Change-Id: Ie18bfbb2f3354ba3645799857061dc20de7f6d84
---
M src/soc/mediatek/mt8196/Makefile.mk
A src/soc/mediatek/mt8196/clkbuf_ctl.c
A src/soc/mediatek/mt8196/include/soc/clkbuf_ctl.h
3 files changed, 874 insertions(+), 0 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/41/85841/6