The only option to make HECI1 function disable on Elkhart Lake SoC platform is using SBI under SMM mode. List of changes: 1. Drop `HeciEnabled` from dt and dt chip configuration. 2. Replace all logic that disables HECI1 based on the `HeciEnabled` chip config with `DISABLE_HECI1_AT_PRE_BOOT` config. Mainboards that choose to make HECI1 enable during boot don't override `heci1 disable` config. Signed-off-by: Subrata Banik <subratabanik@google.com> Change-Id: I76c625e6221fdef1343599e7dbc7739caa91bf98 Reviewed-on: https://review.coreboot.org/c/coreboot/+/60727 Tested-by: build bot (Jenkins) <no-reply@coreboot.org> Reviewed-by: Sheng Lean Tan <sheng.tan@9elements.com>