x86/apic: Remove unused phys_pkg_id() callback

Now that the core code does not use this monstrosity anymore, it's time to
put it to rest.

The only real purpose was to read the APIC ID on UV and VSMP systems for
the actual evaluation. That's what the core code does now.

For doing the actual shift operation there is truly no APIC callback
required.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Juergen Gross <jgross@suse.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Tested-by: Michael Kelley <mhklinux@outlook.com>
Tested-by: Zhang Rui <rui.zhang@intel.com>
Tested-by: Wang Wendy <wendy.wang@intel.com>
Tested-by: K Prateek Nayak <kprateek.nayak@amd.com>
Link: https://lore.kernel.org/r/20240212153625.516536121@linutronix.de