irqchip: sun7i/sun6i: Disable NMI before registering the handler

It is advisable to disable the NMI before registering the IRQ handler as
registering the IRQ handler unmasks the IRQ on the GIC, so if U-Boot has
left the NMI enabled and the NMI pin is active we will immediately get
an interrupt before any driver has claimed the downstream interrupt of
the NMI.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Carlo Caione <carlo@caione.org>
Cc: maxime.ripard@free-electrons.com
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-sunxi@googlegroups.com
Link: http://lkml.kernel.org/r/1395939759-11135-3-git-send-email-carlo@caione.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

drivers/irqchip/irq-sunxi-nmi.c

@@ -179,12 +179,12 @@ static int __init sunxi_sc_nmi_irq_init(struct device_node *node,
 	gc->chip_types[1].regs.type		= reg_offs->ctrl;
 	gc->chip_types[1].handler		= handle_edge_irq;
 
-	irq_set_handler_data(irq, domain);
-	irq_set_chained_handler(irq, sunxi_sc_nmi_handle_irq);
-
 	sunxi_sc_nmi_write(gc, reg_offs->enable, 0);
 	sunxi_sc_nmi_write(gc, reg_offs->pend, 0x1);
 
+	irq_set_handler_data(irq, domain);
+	irq_set_chained_handler(irq, sunxi_sc_nmi_handle_irq);
+
 	return 0;
 
 fail_irqd_remove: