volteer: Remove DisplayPort HPD GPIOs
volteer: Remove DisplayPort HPD GPIOs

This function is already handled by the AP's internal mux, and the GPIOs
were already unused.

BUG=b:157609784
TEST=make buildall
BRANCH=none

Change-Id: I2969ccbf9713d87ab24c9c1a87d917f01d303078
Signed-off-by: Abe Levkoy <2e1ad7039298f93262cf06bbb457275fb3e2ecb5@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2264479
Reviewed-by: Keith Short <f6d578f97033c25f1206cb57d52f358974c82954@chromium.org>
Commit-Queue: Keith Short <f6d578f97033c25f1206cb57d52f358974c82954@chromium.org>

coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec