iommu/arm-smmu: Axe a useless test in 'arm_smmu_master_alloc_smes()'

'iommu_group_get_for_dev()' never returns NULL, so this test can be removed.
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Will Deacon <will@kernel.org>

drivers/iommu/arm-smmu.c

@@ -1054,8 +1054,6 @@ static int arm_smmu_master_alloc_smes(struct device *dev)
 	}
 
 	group = iommu_group_get_for_dev(dev);
-	if (!group)
-		group = ERR_PTR(-ENOMEM);
 	if (IS_ERR(group)) {
 		ret = PTR_ERR(group);
 		goto out_err;