Don't set a default bus type for the Chrome EC on x86. The platform
must select the bus, typically LPC or ESPI.
BUG=b:140055300
TEST=Build tested only
Change-Id: I736cb9e43292a1b228cd083ca81a8e5db383e878
Signed-off-by: Martin Roth <martinroth@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/35154
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-by: Furquan Shaikh <furquan@google.com>
30d3c9ed48