iommu/amd: Move add_special_device() to __init

The function is only called by other __init functions, so it
can be moved to __init too.
Reviewed-by: NShuah Khan <shuahkhan@gmail.com>
Signed-off-by: NJoerg Roedel <joro@8bytes.org>

drivers/iommu/amd_iommu_init.c

@@ -703,7 +703,7 @@ static void __init set_dev_entry_from_acpi(struct amd_iommu *iommu,
 	set_iommu_for_device(iommu, devid);
 }
 
-static int add_special_device(u8 type, u8 id, u16 devid)
+static int __init add_special_device(u8 type, u8 id, u16 devid)
 {
 	struct devid_map *entry;
 	struct list_head *list;