UBI: fix error return code

Set the return variable to an error code as done elsewhere in the function.

A simplified version of the semantic match that finds this problem is as
follows: (http://coccinelle.lip6.fr/)

// <smpl>
(
if@p1 (\(ret < 0\|ret != 0\))
{ ... return ret; }
|
ret@p1 = 0
)
... when != ret = e1
when != &ret
*if(...)
{
... when != ret = e2
when forall
return ret;
}

// </smpl>

Signed-off-by: Julia Lawall <[e-mail]>
Reviewed-by: Richard Weinberger <[e-mail]>

drivers/mtd/ubi/attach.c

···
 		struct ubi_attach_info *scan_ai;
 
 		scan_ai = alloc_ai("ubi_ckh_aeb_slab_cache");
-		if (!scan_ai)
+		if (!scan_ai) {
+			err = -ENOMEM;
 			goto out_wl;
+		}
 
 		err = scan_all(ubi, scan_ai, 0);
 		if (err) {

drivers/mtd/ubi/build.c

···
 	ubi_wl_entry_slab = kmem_cache_create("ubi_wl_entry_slab",
 					      sizeof(struct ubi_wl_entry),
 					      0, 0, NULL);
-	if (!ubi_wl_entry_slab)
+	if (!ubi_wl_entry_slab) {
+		err = -ENOMEM;
 		goto out_dev_unreg;
+	}
 
 	err = ubi_debugfs_init();
 	if (err)