Fix i8259 kernel crash on ML510

[Roderick Colenbrander <thunderbird2k@gmail.com>]

>From 11a2072b285c2eb0f19980ad729229d4ebf22291 Mon Sep 17 00:00:00 2001
From: Roderick Colenbrander <colenbrander@CE202.(none)>
Date: Thu, 3 Sep 2009 15:11:08 +0200
Subject: [PATCH] This patch fixes a null pointer exception caused by
removal of 'ack()' for level interrupts in the Xilinx interrupt driver.

---
 arch/powerpc/sysdev/xilinx_intc.c |    1 -
 1 files changed, 0 insertions(+), 1 deletions(-)

diff --git a/arch/powerpc/sysdev/xilinx_intc.c
b/arch/powerpc/sysdev/xilinx_intc.c
index 3ee1fd3..40edad5 100644
--- a/arch/powerpc/sysdev/xilinx_intc.c
+++ b/arch/powerpc/sysdev/xilinx_intc.c
@@ -234,7 +234,6 @@ static void xilinx_i8259_cascade(unsigned int irq,
struct irq_desc *desc)
 		generic_handle_irq(cascade_irq);
 
 	/* Let xilinx_intc end the interrupt */
-	desc->chip->ack(irq);
 	desc->chip->unmask(irq);
 }
 
-- 
1.6.0.4