iommu/vt-d: Fix 64-bit accesses to 32-bit DMAR_GSTS_REG

This is a 32-bit register. Apparently harmless on real hardware, but
causing justified warnings in simulation.

Signed-off-by: CQ Tang <cq.tang@intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Cc: stable@vger.kernel.org
diff --git a/drivers/iommu/intel_irq_remapping.c b/drivers/iommu/intel_irq_remapping.c
index 1fae188..e9b241b 100644
--- a/drivers/iommu/intel_irq_remapping.c
+++ b/drivers/iommu/intel_irq_remapping.c
@@ -629,7 +629,7 @@
 
 	raw_spin_lock_irqsave(&iommu->register_lock, flags);
 
-	sts = dmar_readq(iommu->reg + DMAR_GSTS_REG);
+	sts = readl(iommu->reg + DMAR_GSTS_REG);
 	if (!(sts & DMA_GSTS_IRES))
 		goto end;