cpu/x86/mp_init.c: Keep track of initial lapic ID inside device_path

It's quite confusing to keep track of lapic ID inside the device
struct and initial lapic ID inside an array.

Change-Id: I4d9f8d23c0b0e5c142f6907593428d8509e4e7bb
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/64342
Reviewed-by: Maximilian Brune <maximilian.brune@9elements.com>
Reviewed-by: Patrick Rudolph <siro@das-labor.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/device/cpu_device.c

@@ -13,6 +13,7 @@ struct device *add_cpu_device(struct bus *cpu_bus, unsigned int apic_id,
 	/* Build the CPU device path */
 	cpu_path.type = DEVICE_PATH_APIC;
 	cpu_path.apic.apic_id = apic_id;
+	cpu_path.apic.initial_lapicid = apic_id;
 
 	/* Update CPU in devicetree. */
 	if (enabled)