soc/intel/common: add Kconfig to enable/disable the ACPI PM timer

Currently, the ACPI PM timer state gets set in devicetree by the option
PmTimerDisabled. However, it is not board design dependent. Thus, add a
user-selectable Kconfig option.

Disabling the PM ACPI Timer is only valid when PM Timer emulation is
supported and is only possible, when there is a hardware PM Timer (APL
does not have one for example). SoCs, where the hardware PM Timer can be
disabled must select `PM_ACPI_TIMER_OPTIONAL`.

This new Kconfig gets used in the follow-up commits of this series.

Change-Id: I7f607f277eb14f84a7370ffb25a13226e7ccc917
Signed-off-by: Michael Niewöhner <foss@mniewoehner.de>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/45952
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Nico Huber <nico.h@gmx.de>

src/soc/intel/common/block/pmc/Kconfig

@@ -43,3 +43,25 @@ config PMC_LOW_POWER_MODE_PROGRAM
 	help
 	  Enable this for PMC devices to perform registers programming
 	  to ensure low power in active idle scenario.
+
+config PM_ACPI_TIMER_OPTIONAL
+	bool
+	default n
+	help
+	  This needs to be selected by SoCs, where the hardware PM Timer
+	  can be disabled, to show the ACPI PM Timer Kconfig in menuconfig.
+
+if PM_ACPI_TIMER_OPTIONAL
+
+config USE_PM_ACPI_TIMER
+	bool "Enable ACPI PM timer"
+	default y
+	help
+	  This should be disabled for devices running on battery since
+	  it can draw much power. Further, it must be disabled, if S0ix
+	  is enabled.
+
+	  Disabling this option also stops the hardware TCO timer and makes
+	  the TCO watchdog unavailable.
+
+endif # PM_ACPI_TIMER_OPTIONAL