genirq: Reuse existing can set affinty check

Add a !desc check while at it.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

kernel/irq/proc.c

@@ -66,8 +66,7 @@ static ssize_t irq_affinity_proc_write(struct file *file,
 	cpumask_var_t new_value;
 	int err;
 
-	if (!irq_to_desc(irq)->irq_data.chip->irq_set_affinity || no_irq_affinity ||
-	    irq_balancing_disabled(irq))
+	if (!irq_can_set_affinity(irq) || no_irq_affinity)
 		return -EIO;
 
 	if (!alloc_cpumask_var(&new_value, GFP_KERNEL))