MIPS: Mark cascade and low level interrupts IRQF_NO_THREAD

Mark interrupts with no_action handler, cascade interrupts, low level
interrupts (bus error, halt ..) with IRQF_NO_THREAD to exclude them
from forced threading.

Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mips@linux-mips.org
Cc: Wu Zhangjin <wuzhangjin@gmail.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/cobalt/irq.c b/arch/mips/cobalt/irq.c
index cb9bf82..965c777 100644
--- a/arch/mips/cobalt/irq.c
+++ b/arch/mips/cobalt/irq.c
@@ -48,6 +48,7 @@
 static struct irqaction cascade = {
 	.handler	= no_action,
 	.name		= "cascade",
+	.flags		= IRQF_NO_THREAD,
 };
 
 void __init arch_init_irq(void)