ec/google/chromeec: Drop 'choice' selections for EC and PD firmware
Since the EC and PD firmware sources are now limited to two options -
'none' and 'external' - drop the choice selection and make the
EC and PD external options independent.
TEST=build google/lulu with external EC binary using existing defconfig
Change-Id: Ie37ff3a188b414fd099fbb344858bca4df419086
Signed-off-by: Matt DeVillier <matt.devillier@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/83639
Reviewed-by: Julius Werner <jwerner@chromium.org>
Reviewed-by: Felix Singer <service+coreboot-gerrit@felixsinger.de>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>