iommu/exynos: Use generic group callback

Since iommu_group_get_for_dev() already tries iommu_group_get() and will
not call ops->device_group if the group is already non-NULL, the check
in get_device_iommu_group() is always redundant and it reduces to a
duplicate of the generic version; let's just use that one instead.

Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

drivers/iommu/exynos-iommu.c

@@ -1238,17 +1238,6 @@ static phys_addr_t exynos_iommu_iova_to_phys(struct iommu_domain *iommu_domain,
 	return phys;
 }
 
-static struct iommu_group *get_device_iommu_group(struct device *dev)
-{
-	struct iommu_group *group;
-
-	group = iommu_group_get(dev);
-	if (!group)
-		group = iommu_group_alloc();
-
-	return group;
-}
-
 static int exynos_iommu_add_device(struct device *dev)
 {
 	struct exynos_iommu_owner *owner = dev->archdata.iommu;
@@ -1344,7 +1333,7 @@ static const struct iommu_ops exynos_iommu_ops = {
 	.unmap = exynos_iommu_unmap,
 	.map_sg = default_iommu_map_sg,
 	.iova_to_phys = exynos_iommu_iova_to_phys,
-	.device_group = get_device_iommu_group,
+	.device_group = generic_device_group,
 	.add_device = exynos_iommu_add_device,
 	.remove_device = exynos_iommu_remove_device,
 	.pgsize_bitmap = SECT_SIZE | LPAGE_SIZE | SPAGE_SIZE,