x86/cpu/topology: Simplify APIC registration

Having the same check whether the number of assigned CPUs has reached the
nr_cpu_ids limit twice in the same code path is pointless. Repeating the
information that CPUs are ignored over and over is also pointless noise.

Remove the redundant check and reduce the noise by using a pr_warn_once().

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/20240213210252.050264369@linutronix.de