genirq: Convert irq_desc.lock to raw_spinlock

Convert locks which cannot be sleeping locks in preempt-rt to
raw_spinlocks.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Ingo Molnar <mingo@elte.hu>

arch/powerpc/platforms/pseries/xics.c

@@ -906,7 +906,7 @@ void xics_migrate_irqs_away(void)
 		    || desc->chip->set_affinity == NULL)
 			continue;
 
-		spin_lock_irqsave(&desc->lock, flags);
+		raw_spin_lock_irqsave(&desc->lock, flags);
 
 		status = rtas_call(ibm_get_xive, 1, 3, xics_status, irq);
 		if (status) {
@@ -930,7 +930,7 @@ void xics_migrate_irqs_away(void)
 		cpumask_setall(irq_to_desc(virq)->affinity);
 		desc->chip->set_affinity(virq, cpu_all_mask);
 unlock:
-		spin_unlock_irqrestore(&desc->lock, flags);
+		raw_spin_unlock_irqrestore(&desc->lock, flags);
 	}
 }
 #endif