x86/apic: Use a proper define for invalid ACPI CPU ID

The ACPI ID for CPUs is preset with U32_MAX which is completely non
obvious. Use a proper define for it.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Michael Kelley <mhklinux@outlook.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Link: https://lore.kernel.org/r/20240212154640.177504138@linutronix.de