x86-32, NUMA: Make apic->x86_32_numa_cpu_node() optional

NUMAQ is the only meaningful user of this callback and
setup_local_APIC() the only callsite.  Stop torturing everyone else by
making the callback optional and removing all the boilerplate
implementations and assignments.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>

arch/x86/kernel/apic/es7000_32.c

@@ -510,11 +510,6 @@ static void es7000_setup_apic_routing(void)
 		nr_ioapics, cpumask_bits(es7000_target_cpus())[0]);
 }
 
-static int es7000_numa_cpu_node(int cpu)
-{
-	return 0;
-}
-
 static int es7000_cpu_present_to_apicid(int mps_cpu)
 {
 	if (!mps_cpu)
@@ -688,7 +683,6 @@ struct apic __refdata apic_es7000_cluster = {
 	.safe_wait_icr_idle		= native_safe_apic_wait_icr_idle,
 
 	.x86_32_early_logical_apicid	= es7000_early_logical_apicid,
-	.x86_32_numa_cpu_node		= es7000_numa_cpu_node,
 };
 
 struct apic __refdata apic_es7000 = {
@@ -752,5 +746,4 @@ struct apic __refdata apic_es7000 = {
 	.safe_wait_icr_idle		= native_safe_apic_wait_icr_idle,
 
 	.x86_32_early_logical_apicid	= es7000_early_logical_apicid,
-	.x86_32_numa_cpu_node		= es7000_numa_cpu_node,
 };