x86: use cpumask_of_cpu()

Use cpumask_of_cpu() rather than the pair of cpus_clear() and cpu_set().
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/x86/kernel/genapic_flat_64.c

@@ -138,12 +138,9 @@ static cpumask_t physflat_target_cpus(void)
 
 static cpumask_t physflat_vector_allocation_domain(int cpu)
 {
-	cpumask_t domain = CPU_MASK_NONE;
-	cpu_set(cpu, domain);
-	return domain;
+	return cpumask_of_cpu(cpu);
 }
 
-
 static void physflat_send_IPI_mask(cpumask_t cpumask, int vector)
 {
 	send_IPI_mask_sequence(cpumask, vector);

arch/x86/kernel/io_apic_64.c

@@ -1362,9 +1362,7 @@ static int ioapic_retrigger_irq(unsigned int irq)
 	unsigned long flags;
 
 	spin_lock_irqsave(&vector_lock, flags);
-	cpus_clear(mask);
-	cpu_set(first_cpu(cfg->domain), mask);
-
+	mask = cpumask_of_cpu(first_cpu(cfg->domain));
 	send_IPI_mask(mask, cfg->vector);
 	spin_unlock_irqrestore(&vector_lock, flags);