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: Thomas Gleixner <[e-mail]>
Cc: [e-mail]
Signed-off-by: Ingo Molnar <[e-mail]>

drivers/iommu/dmar.c

···
 		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;