UBI: Add fastmap stuff to attach.c

- Export compare_lebs() as fastmap needs this function.
- Implement fastmap scan logic.
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>

drivers/mtd/ubi/build.c

@@ -990,7 +990,7 @@ int ubi_attach_mtd_dev(struct mtd_info *mtd, int ubi_num,
 	if (err)
 		goto out_free;
 
-	err = ubi_attach(ubi);
+	err = ubi_attach(ubi, 0);
 	if (err) {
 		ubi_err("failed to attach mtd%d, error %d", mtd->index, err);
 		goto out_debugging;

drivers/mtd/ubi/ubi.h

@@ -710,7 +710,7 @@ struct ubi_ainf_volume *ubi_find_av(const struct ubi_attach_info *ai,
 void ubi_remove_av(struct ubi_attach_info *ai, struct ubi_ainf_volume *av);
 struct ubi_ainf_peb *ubi_early_get_peb(struct ubi_device *ubi,
 				       struct ubi_attach_info *ai);
-int ubi_attach(struct ubi_device *ubi);
+int ubi_attach(struct ubi_device *ubi, int force_scan);
 void ubi_destroy_ai(struct ubi_attach_info *ai);
 
 /* vtbl.c */