Revert "genirq: Restrict effective affinity to interrupts actually using it"

This reverts commit 74def747.

The change to the helper function is only correct for the /proc/irq/
readout usage, but breaks the existing x86 usage of that function.
Reported-by: Yanko Kaneti <yaneti@declera.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Marc Zyngier <marc.zyngier@arm.com>

include/linux/irq.h

@@ -783,10 +783,7 @@ static inline struct cpumask *irq_data_get_affinity_mask(struct irq_data *d)
 static inline
 struct cpumask *irq_data_get_effective_affinity_mask(struct irq_data *d)
 {
-	if (!cpumask_empty(d->common->effective_affinity))
-		return d->common->effective_affinity;
-
-	return d->common->affinity;
+	return d->common->effective_affinity;
 }
 static inline void irq_data_update_effective_affinity(struct irq_data *d,
 						      const struct cpumask *m)