soc/intel/common: Rework acpi/cpu.asl

Use acpigen_write_processor_cnot to implement notifications to the CPU.

Change-Id: Id64f9857bbd7db520c94de949db8f823f71d6dae
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-on: https://review.coreboot.org/c/29891
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Duncan Laurie <dlaurie@chromium.org>

src/soc/intel/common/block/acpi/acpi.c

@@ -436,6 +436,12 @@ void generate_cpu_entries(struct device *device)
 			acpigen_pop_len();
 		}
 	}
+	/* PPKG is usually used for thermal management
+	   of the first and only package. */
+	acpigen_write_processor_package("PPKG", 0, cores_per_package);
+
+	/* Add a method to notify processor nodes */
+	acpigen_write_processor_cnot(cores_per_package);
 }
 
 #if IS_ENABLED(CONFIG_SOC_INTEL_COMMON_ACPI_WAKE_SOURCE)