Backport a change that updates the effective affinity mask. The Armada IRQ
controller only supports setting the affinity to a single CPU, and the IRQ
subsystem needs to know about that.

Signed-off-by: Felix Fietkau <nbd@nbd.name>
---
--- a/drivers/irqchip/irq-armada-370-xp.c
+++ b/drivers/irqchip/irq-armada-370-xp.c
@@ -251,6 +251,8 @@ static int armada_xp_set_affinity(struct
 	writel(reg, main_int_base + ARMADA_370_XP_INT_SOURCE_CTL(hwirq));
 	raw_spin_unlock(&irq_controller_lock);
 
+	cpumask_copy(irq_data_get_affinity_mask(d), cpumask_of(cpu));
+
 	return IRQ_SET_MASK_OK;
 }
 #endif