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/include/device/path.h

@@ -73,6 +73,7 @@ struct spi_path {
 };
 
 struct apic_path {
+	unsigned int initial_lapicid;
 	unsigned int apic_id;
 	unsigned int package_id;
 	unsigned int node_id;