irqchip: orion: clear bridge cause register on init

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>
Cc: <stable@vger.kernel.org> # v3.10+
Signed-off-by: Jason Cooper <jason@lakedaemon.net>
diff --git a/drivers/irqchip/irq-orion.c b/drivers/irqchip/irq-orion.c
index e51d400..4137c3d 100644
--- a/drivers/irqchip/irq-orion.c
+++ b/drivers/irqchip/irq-orion.c
@@ -180,8 +180,9 @@
 	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);