mtd: ubi: wl: Fix error return code in ubi_wl_init()

Fix to return error code -ENOMEM from the kmem_cache_alloc() error
handling case instead of 0, as done elsewhere in this function.

Fixes: f78e562 ("ubi: fastmap: Erase outdated anchor PEBs during
attach")
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Reviewed-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

drivers/mtd/ubi/wl.c

@@ -1617,8 +1617,10 @@ int ubi_wl_init(struct ubi_device *ubi, struct ubi_attach_info *ai)
 		cond_resched();
 
 		e = kmem_cache_alloc(ubi_wl_entry_slab, GFP_KERNEL);
-		if (!e)
+		if (!e) {
+			err = -ENOMEM;
 			goto out_free;
+		}
 
 		e->pnum = aeb->pnum;
 		e->ec = aeb->ec;
@@ -1637,8 +1639,10 @@ int ubi_wl_init(struct ubi_device *ubi, struct ubi_attach_info *ai)
 			cond_resched();
 
 			e = kmem_cache_alloc(ubi_wl_entry_slab, GFP_KERNEL);
-			if (!e)
+			if (!e) {
+				err = -ENOMEM;
 				goto out_free;
+			}
 
 			e->pnum = aeb->pnum;
 			e->ec = aeb->ec;