Change in coreboot[master]: mb/google/dedede/var/drawcia: Add support to handle pen detection

[Chen Wisley (Code Review)]

Attention is currently required from: Martin Roth, Henry Sun, Evan Green.
Hello build bot (Jenkins), Patrick Georgi, Martin Roth, Henry Sun, Evan Green, Karthik Ramasubramanian,

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

https://review.coreboot.org/c/coreboot/+/49469

to look at the new patch set (#6).

Change subject: mb/google/dedede/var/drawcia: Add support to handle pen detection
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mb/google/dedede/var/drawcia: Add support to handle pen detection

Drawlat/Drawman/Drawcia share the same AP firmware, and only Drawcia is
convertible. So, use tablet mode bit of fw config to override GPP_C12.

BUG=b:177618684
TEST=emerge-dedede coreboot, check evtest if SW_PEN_INSERTED event
(value:1/0) when insert/eject pen, and eject pen to wake system from s0ix

Signed-off-by: Wisley Chen 
Change-Id: I503873afb48384168dcd8a822c7246655898356e
---
M src/mainboard/google/dedede/variants/drawcia/Makefile.inc
A src/mainboard/google/dedede/variants/drawcia/gpio.c
M src/mainboard/google/dedede/variants/drawcia/overridetree.cb
3 files changed, 34 insertions(+), 0 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/69/49469/6