tcpc/mt6370: add MediaTek MT6370 TCPC driver.

BUG=b:80160923 b:111908397
BRANCH=None
TEST=make flash_ec BOARD=kukui
TEST=plug-in PD charger, check negotiate success, TCPC is sinking 5v/12v.
TEST=plug-in peripheral; pd dualrole on; check TCPC is sourcing.

Change-Id: I3587a7df40ae3a6254435d3cd133e1ee3000e36b
Signed-off-by: Yilun Lin <yllin@google.com>
Reviewed-on: https://chromium-review.googlesource.com/1158264
Commit-Ready: Yilun Lin <yllin@chromium.org>
Tested-by: Yilun Lin <yllin@chromium.org>
Reviewed-by: Jett Rink <jettrink@chromium.org>
4 files changed