iommu/arm-smmu: Drop if with an always false condition

The remove and shutdown callback are only called after probe completed
successfully. In this case platform_set_drvdata() was called with a
non-NULL argument and so smmu is never NULL. Other functions in this
driver also don't check for smmu being non-NULL before using it.

Also note that returning an error code from a remove callback doesn't
result in the device staying bound. It's still removed and devm allocated
resources are freed (among others *smmu and the register mapping). So
after an early exit to iommu device stayed around and using it probably
oopses.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/20230321084125.337021-2-u.kleine-koenig@pengutronix.de
Signed-off-by: Joerg Roedel <jroedel@suse.de>

Author: Uwe Kleine-König

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

@@ -2195,9 +2195,6 @@ static void arm_smmu_device_shutdown(struct platform_device *pdev)
 {
 	struct arm_smmu_device *smmu = platform_get_drvdata(pdev);
 
-	if (!smmu)
-		return;
-
 	if (!bitmap_empty(smmu->context_map, ARM_SMMU_MAX_CBS))
 		dev_notice(&pdev->dev, "disabling translation\n");
 
@@ -2218,9 +2215,6 @@ static int arm_smmu_device_remove(struct platform_device *pdev)
 {
 	struct arm_smmu_device *smmu = platform_get_drvdata(pdev);
 
-	if (!smmu)
-		return -ENODEV;
-
 	iommu_device_unregister(&smmu->iommu);
 	iommu_device_sysfs_remove(&smmu->iommu);