sparc64: Disable timer interrupts in fixup_irqs().

When a CPU is offlined, we leave the timer interrupts disabled
because fixup_irqs() does not explicitly take care of that case.

Fix this by invoking tick_ops->disable_irq().

Based upon analysis done by Paul E. McKenney.

Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/arch/sparc64/kernel/irq.c b/arch/sparc64/kernel/irq.c
index 9b6689d..2396388 100644
--- a/arch/sparc64/kernel/irq.c
+++ b/arch/sparc64/kernel/irq.c
@@ -792,6 +792,8 @@
 		}
 		spin_unlock_irqrestore(&irq_desc[irq].lock, flags);
 	}
+
+	tick_ops->disable_irq();
 }
 #endif