soc/intel/cannonlake: Enable ACPI timer emulation if PM timer is disabled

Add a check to enable ACPI timer emulation only when the APCI PM timer
is disabled.

Change-Id: I21c0b89218d0df9336e0b0e15f1b575b8508fb96
Signed-off-by: Aamir Bohra <aamir.bohra@intel.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/34563
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Furquan Shaikh <furquan@google.com>
Reviewed-by: Subrata Banik <subrata.banik@intel.com>

src/soc/intel/cannonlake/cpu.c

@@ -384,8 +384,14 @@ static void configure_thermal_target(void)
  */
 static void enable_pm_timer_emulation(void)
 {
-	/* ACPI PM timer emulation */
+	const struct soc_intel_cannonlake_config *config;
 	msr_t msr;
+
+	config = config_of_path(SA_DEVFN_ROOT);
+
+	/* Enable PM timer emulation only if ACPI PM timer is disabled */
+	if (!config->PmTimerDisabled)
+		return;
 	/*
 	 * The derived frequency is calculated as follows:
 	 *    (CTC_FREQ * msr[63:32]) >> 32 = target frequency.