x86, apic: Remove smp_callin_clear_local_apic callback

Since commit b5660ba76b ("x86, platforms: Remove NUMAQ") removed NUMAQ,
the smp_callin_clear_local_apic() apic callback has been obsolete.
Remove it.

Signed-off-by: David Rientjes <rientjes@google.com>
Link: http://lkml.kernel.org/r/alpine.DEB.2.02.1407302349040.17503@chino.kir.corp.google.com
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

arch/x86/kernel/apic/apic_noop.c

@@ -169,7 +169,6 @@ struct apic apic_noop = {
 	.wakeup_secondary_cpu		= noop_wakeup_secondary_cpu,
 
 	.wait_for_init_deassert		= false,
-	.smp_callin_clear_local_apic	= NULL,
 	.inquire_remote_apic		= NULL,
 
 	.read				= noop_apic_read,