google/kahlee/grunt: Move ASL to variants

Move the apci/ to the baseboard and move mainboard.asl to
each variant.

BUG=b:71873651
TEST=build
BRANCH=none

Change-Id: I8a829f2946e4b280cd78574eb8dbda6c2a9a1028
Signed-off-by: Marc Jones <marcj303@gmail.com>
Reviewed-on: https://review.coreboot.org/23229
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Richard Spiegel <richard.spiegel@silverbackltd.com>
16 files changed