ACPI / processor: Introduce apic_id in struct processor to save parsed APIC id

For cpu hot add, we evaluate _MAT or parse MADT twice to get APIC id,
here is the code logic:
acpi_processor_add()
	acpi_processor_get_info()
		acpi_get_cpuid() will evaluate _MAT or parse MADT;
	acpi_processor_hotadd_init()
		acpi_map_lsapic() will evaluate _MAT again;

This can be done more effectively, this patch introduces apic_id in struct
processor to save parsed APIC id, and then we can use it and remove the
duplicated _MAT evaluation.

Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Signed-off-by: Hanjun Guo <hanjun.guo@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
diff --git a/drivers/acpi/acpi_processor.c b/drivers/acpi/acpi_processor.c
index f29e06e..f89f914 100644
--- a/drivers/acpi/acpi_processor.c
+++ b/drivers/acpi/acpi_processor.c
@@ -270,7 +270,9 @@
 		device_declaration = 1;
 		pr->acpi_id = value;
 	}
-	cpu_index = acpi_get_cpuid(pr->handle, device_declaration, pr->acpi_id);
+	pr->apic_id = acpi_get_apicid(pr->handle, device_declaration,
+					pr->acpi_id);
+	cpu_index = acpi_map_cpuid(pr->apic_id, pr->acpi_id);
 
 	/* Handle UP system running SMP kernel, with no LAPIC in MADT */
 	if (!cpu0_initialized && (cpu_index == -1) &&