x86/ioapic: Simplify setup_ioapic_ids_from_mpc_nocheck()

No need to go through APIC callbacks. It's already established that this is
an ancient APIC. So just copy the present mask and use the direct physid*
functions all over the place.

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/20240212154639.181901887@linutronix.de