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

Use acpigen_write_processor_cnot to implement notifications to the CPU.

Change-Id: I93c11e89da34c5432c6ce0415998b47bad339763
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-on: https://review.coreboot.org/c/29889
Reviewed-by: Duncan Laurie <dlaurie@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/soc/intel/braswell/acpi.c

@@ -448,6 +448,13 @@ 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, pattrs->num_cpus);
+
+	/* Add a method to notify processor nodes */
+	acpigen_write_processor_cnot(pattrs->num_cpus);
 }
 
 unsigned long acpi_madt_irq_overrides(unsigned long current)