UBI: Fastmap: Set used_ebs only for static volumes

If we set it for dynamic ones we might confuse various self checks.
Signed-off-by: Richard Weinberger <richard@nod.at>

drivers/mtd/ubi/fastmap.c

@@ -136,14 +136,15 @@ static struct ubi_ainf_volume *add_vol(struct ubi_attach_info *ai, int vol_id,
 	if (!av)
 		goto out;
 
-	av->highest_lnum = av->leb_count = 0;
+	av->highest_lnum = av->leb_count = av->used_ebs = 0;
 	av->vol_id = vol_id;
-	av->used_ebs = used_ebs;
 	av->data_pad = data_pad;
 	av->last_data_size = last_eb_bytes;
 	av->compat = 0;
 	av->vol_type = vol_type;
 	av->root = RB_ROOT;
+	if (av->vol_type == UBI_STATIC_VOLUME)
+		av->used_ebs = used_ebs;
 
 	dbg_bld("found volume (ID %i)", vol_id);