iommu/arm-smmu-v3: Use msi_get_virq()

Let the core code fiddle with the MSI descriptor retrieval.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Robin Murphy <robin.murphy@arm.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/20211210221815.089008198@linutronix.de

drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c

@@ -3154,7 +3154,6 @@ static void arm_smmu_write_msi_msg(struct msi_desc *desc, struct msi_msg *msg)
 
 static void arm_smmu_setup_msis(struct arm_smmu_device *smmu)
 {
-	struct msi_desc *desc;
 	int ret, nvec = ARM_SMMU_MAX_MSIS;
 	struct device *dev = smmu->dev;
 
@@ -3182,21 +3181,9 @@ static void arm_smmu_setup_msis(struct arm_smmu_device *smmu)
 		return;
 	}
 
-	for_each_msi_entry(desc, dev) {
-		switch (desc->msi_index) {
-		case EVTQ_MSI_INDEX:
-			smmu->evtq.q.irq = desc->irq;
-			break;
-		case GERROR_MSI_INDEX:
-			smmu->gerr_irq = desc->irq;
-			break;
-		case PRIQ_MSI_INDEX:
-			smmu->priq.q.irq = desc->irq;
-			break;
-		default:	/* Unknown */
-			continue;
-		}
-	}
+	smmu->evtq.q.irq = msi_get_virq(dev, EVTQ_MSI_INDEX);
+	smmu->gerr_irq = msi_get_virq(dev, GERROR_MSI_INDEX);
+	smmu->priq.q.irq = msi_get_virq(dev, PRIQ_MSI_INDEX);
 
 	/* Add callback to free MSIs on teardown */
 	devm_add_action(dev, arm_smmu_free_msis, dev);