[IA64] Remove redundant cpu_clear() in __cpu_disable path

The second call to cpu_clear() is redundant, as we've already removed
the CPU from cpu_online_map before calling migrate_platform_irqs().
Signed-off-by: NAlex Chiang <achiang@hp.com>
Signed-off-by: NTony Luck <aegl@agluck-desktop.(none)>

arch/ia64/kernel/smpboot.c

@@ -740,11 +740,10 @@ int __cpu_disable(void)
 
 	if (migrate_platform_irqs(cpu)) {
 		cpu_set(cpu, cpu_online_map);
-		return (-EBUSY);
+		return -EBUSY;
 	}
 
 	remove_siblinginfo(cpu);
-	cpu_clear(cpu, cpu_online_map);
 	fixup_irqs();
 	local_flush_tlb_all();
 	cpu_clear(cpu, cpu_callin_map);