iommu: Remove FIXME comment about user_creatable=true

amd-iommu and intel-iommu are really meant to be used with
-device, so they need user_creatable=true. Remove the FIXME
comment.

Cc: Marcel Apfelbaum <marcel@redhat.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Reviewed-by: NMarcel Apfelbaum <marcel@redhat.com>
Acked-by: NMarcel Apfelbaum <marcel@redhat.com>
Signed-off-by: NEduardo Habkost <ehabkost@redhat.com>
Message-Id: <20170503203604.31462-5-ehabkost@redhat.com>
Signed-off-by: NEduardo Habkost <ehabkost@redhat.com>

hw/i386/amd_iommu.c

@@ -1186,10 +1186,7 @@ static void amdvi_class_init(ObjectClass *klass, void* data)
     dc->vmsd = &vmstate_amdvi;
     dc->hotpluggable = false;
     dc_class->realize = amdvi_realize;
-    /*
-     * FIXME: Set only because we are not sure yet if this device
-     * will be outside the q35 sysbus whitelist.
-     */
+    /* Supported by the pc-q35-* machine types */
     dc->user_creatable = true;
 }
 

hw/i386/intel_iommu.c

@@ -3009,10 +3009,7 @@ static void vtd_class_init(ObjectClass *klass, void *data)
     dc->hotpluggable = false;
     x86_class->realize = vtd_realize;
     x86_class->int_remap = vtd_int_remap;
-    /*
-     * FIXME: Set only because we are not sure yet if this device
-     * will be outside the q35 sysbus whitelist.
-     */
+    /* Supported by the pc-q35-* machine types */
     dc->user_creatable = true;
 }