ACPI: Add helpers for CBMEM_ID_POWER_STATE

Create uniform logging for the (unlikely) case of a CBMEM
entry disappearing.

Change-Id: I7c5414a03d869423c8ae5192a990fde5f9582f2d
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/49817
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-by: Felix Held <felix-coreboot@felixheld.de>
diff --git a/src/soc/intel/apollolake/pmutil.c b/src/soc/intel/apollolake/pmutil.c
index 6e96b57..1d4a558 100644
--- a/src/soc/intel/apollolake/pmutil.c
+++ b/src/soc/intel/apollolake/pmutil.c
@@ -3,9 +3,9 @@
 #define __SIMPLE_DEVICE__
 
 #include <acpi/acpi.h>
+#include <acpi/acpi_pm.h>
 #include <arch/io.h>
 #include <device/mmio.h>
-#include <cbmem.h>
 #include <console/console.h>
 #include <cpu/x86/msr.h>
 #include <device/device.h>
@@ -185,12 +185,10 @@
 
 int soc_get_rtc_failed(void)
 {
-	const struct chipset_power_state *ps = cbmem_find(CBMEM_ID_POWER_STATE);
+	const struct chipset_power_state *ps;
 
-	if (!ps) {
-		printk(BIOS_ERR, "Could not find power state in cbmem, RTC init aborted\n");
+	if (acpi_pm_state_for_rtc(&ps) < 0)
 		return 1;
-	}
 
 	return rtc_failed(ps->gen_pmcon1);
 }