x86, iommu: Mark DMAR IRQ as non-threaded

Mark this lowlevel IRQ handler as non-threaded. This prevents a boot
crash when "threadirqs" is on the kernel commandline. Also the
interrupt handler is handling hardware critical events which should
not be delayed into a thread.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: stable@kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>

drivers/iommu/dmar.c

@@ -1388,7 +1388,7 @@ int dmar_set_interrupt(struct intel_iommu *iommu)
 		return ret;
 	}
 
-	ret = request_irq(irq, dmar_fault, 0, iommu->name, iommu);
+	ret = request_irq(irq, dmar_fault, IRQF_NO_THREAD, iommu->name, iommu);
 	if (ret)
 		printk(KERN_ERR "IOMMU: can't request irq\n");
 	return ret;