sparc64: Set IRQF_DISABLED on LDC channel IRQs.

With lots of virtual devices it's easy to generate a lot of
events and chew up the kernel IRQ stack.
Reported-by: Nhyl <heyongli@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

arch/sparc/kernel/ldc.c

@@ -1242,13 +1242,13 @@ int ldc_bind(struct ldc_channel *lp, const char *name)
 	snprintf(lp->tx_irq_name, LDC_IRQ_NAME_MAX, "%s TX", name);
 
 	err = request_irq(lp->cfg.rx_irq, ldc_rx,
-			  IRQF_SAMPLE_RANDOM | IRQF_SHARED,
+			  IRQF_SAMPLE_RANDOM | IRQF_DISABLED | IRQF_SHARED,
 			  lp->rx_irq_name, lp);
 	if (err)
 		return err;
 
 	err = request_irq(lp->cfg.tx_irq, ldc_tx,
-			  IRQF_SAMPLE_RANDOM | IRQF_SHARED,
+			  IRQF_SAMPLE_RANDOM | IRQF_DISABLED | IRQF_SHARED,
 			  lp->tx_irq_name, lp);
 	if (err) {
 		free_irq(lp->cfg.rx_irq, lp);