powerpc/powermac: set IRQF_NO_THREAD for xmon/cascade handlers

The xmon and cascade irq handlers must not run as threads.
pmac_pic_lock is already a raw_spinlock, but the irq flag
IRQF_NO_THREAD needs to be set as well.
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/platforms/powermac/pic.c

@@ -258,13 +258,14 @@ static unsigned int pmac_pic_get_irq(void)
 #ifdef CONFIG_XMON
 static struct irqaction xmon_action = {
 	.handler	= xmon_irq,
-	.flags		= 0,
+	.flags		= IRQF_NO_THREAD,
 	.name		= "NMI - XMON"
 };
 #endif
 
 static struct irqaction gatwick_cascade_action = {
 	.handler	= gatwick_action,
+	.flags		= IRQF_NO_THREAD,
 	.name		= "cascade",
 };