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>

arch/sparc64/kernel/irq.c

@@ -792,6 +792,8 @@ void fixup_irqs(void)
 		}
 		spin_unlock_irqrestore(&irq_desc[irq].lock, flags);
 	}
+
+	tick_ops->disable_irq();
 }
 #endif