irqchip: gic: fix irq_trigger return

The genirq layer expects a 0 in case that the retrigger function is
not able to resend the irq in hardware, but the code is returning
-ENXIO. Fix it.

[ tglx: Reworked comment and changelog ]

Signed-off-by: Abhijeet Dharmapurikar <adharmap@codeaurora.org>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/1363734349-32635-1-git-send-email-sboyd@codeaurora.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

drivers/irqchip/irq-gic.c

@@ -236,7 +236,8 @@ static int gic_retrigger(struct irq_data *d)
 	if (gic_arch_extn.irq_retrigger)
 		return gic_arch_extn.irq_retrigger(d);
 
-	return -ENXIO;
+	/* the genirq layer expects 0 if we can't retrigger in hardware */
+	return 0;
 }
 
 #ifdef CONFIG_SMP