irqchip: orion: clear bridge cause register on init

commit 7b119fd1 upstream.

It is good practice to mask and clear pending irqs on init. We already
mask all irqs, so also clear the bridge irq cause register.
Signed-off-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Tested-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
Signed-off-by: Jason Cooper <jason@lakedaemon.net>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>

drivers/irqchip/irq-orion.c

@@ -180,8 +180,9 @@ static int __init orion_bridge_irq_init(struct device_node *np,
 	gc->chip_types[0].chip.irq_mask = irq_gc_mask_clr_bit;
 	gc->chip_types[0].chip.irq_unmask = irq_gc_mask_set_bit;
 
-	/* mask all interrupts */
+	/* mask and clear all interrupts */
 	writel(0, gc->reg_base + ORION_BRIDGE_IRQ_MASK);
+	writel(0, gc->reg_base + ORION_BRIDGE_IRQ_CAUSE);
 
 	irq_set_handler_data(irq, domain);
 	irq_set_chained_handler(irq, orion_bridge_irq_handler);