soc/intel/cannonlake: Enable low power S0 Idle capability

This patch sets the ACPI FADT flag ACPI_FADT_LOW_POWER_S0
if S0ix is enabled for the platform. This also sets the
FSPUPD to indicate the status of S0ix on the platform.

TEST= Boot to OS and check the ACPI_FADT_LOW_PWR_IDLE_S0 flag
      is set in FACP table - FADT.Flags[21] bit.

Change-Id: I6214ebb61f25ef8b704e60c8474808493c92e6f6
Signed-off-by: Vaibhav Shankar <vaibhav.shankar@intel.com>
Reviewed-on: https://review.coreboot.org/25292
Reviewed-by: Furquan Shaikh <furquan@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
2 files changed