mb/google/kahlee: Implement touchscreen power sequencing

mb/google/kahlee: Implement touchscreen power sequencing

As all variants have a touchscreen option, in baseboard table set the
enable GPIO high and hold in reset during romstage, then release reset
in ramstage. This will allow the touchscreen to make use of the runtime
I2C detect feature (enabled in a subsequent commit) so that an ACPI
device entry is created only for the touchscreen actually present.

This mirrors similar changes made for skyrim, guybrush, and zork.

TEST=tested with rest of patch train

Change-Id: Id235815904dfc093549a1ed529e19974010977c7
Signed-off-by: Matt DeVillier <matt.devillier@amd.corp-partner.google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/69547
Reviewed-by: Martin L Roth <gaumless@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>