iommu/arm-smmu: Retire probe deferral workaround

This reverts commit 229e6ee.

Now that the fundamental ordering issue between arm_smmu_get_by_fwnode()
and iommu_device_register() is resolved, the race condition for client
probe no longer exists either, so retire the specific workaround.

Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/4167c5dfa052d4c8bb780f0a30af63dcfc4ce6c1.1733406914.git.robin.murphy@arm.com
Signed-off-by: Will Deacon <will@kernel.org>

Author: rmurphy-arm

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

@@ -1437,17 +1437,6 @@ static struct iommu_device *arm_smmu_probe_device(struct device *dev)
 			goto out_free;
 	} else {
 		smmu = arm_smmu_get_by_fwnode(fwspec->iommu_fwnode);
-
-		/*
-		 * Defer probe if the relevant SMMU instance hasn't finished
-		 * probing yet. This is a fragile hack and we'd ideally
-		 * avoid this race in the core code. Until that's ironed
-		 * out, however, this is the most pragmatic option on the
-		 * table.
-		 */
-		if (!smmu)
-			return ERR_PTR(dev_err_probe(dev, -EPROBE_DEFER,
-						"smmu dev has not bound yet\n"));
 	}
 
 	ret = -EINVAL;