Change in coreboot[master]: mb/google/volteer: Create APIs for USB-C DP alternate mode support

[Derek Huang (Code Review)]

Attention is currently required from: Derek Huang, Zhuohao Lee, Brandon Breitenstein, Curtis Chen.
Hello build bot (Jenkins), Tim Wawrzynczak, Brandon Breitenstein, Patrick Rudolph, Curtis Chen,

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

https://review.coreboot.org/c/coreboot/+/57139

to look at the new patch set (#7).

Change subject: mb/google/volteer: Create APIs for USB-C DP alternate mode support
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mb/google/volteer: Create APIs for USB-C DP alternate mode support

Create API to detect if any DP device is connected and API to send
the direction from the AP to EC to enter DP mode. These APIs are
called by TCSS common block code.

BUG=b:192947843
TEST=select ENABLE_TCSS_DISPLAY_DETECTION in Kconfig.name. Build
coreboot and update your system. Boot the system, external display
connected on USB-C port should show screen in developer mode or
recovery mode

Signed-off-by: Derek Huang 
Change-Id: Ia7e6dd952d3183ecb76de6d4887ee573ef89bb50
---
M src/mainboard/google/volteer/mainboard.c
M src/soc/intel/common/block/include/intelblocks/tcss.h
M src/soc/intel/common/block/tcss/tcss.c
3 files changed, 131 insertions(+), 1 deletion(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/39/57139/7