ubifs: Force prandom result to __le32

In set_dent_cookie() the result of prandom_u32() is
assinged to an __le32 type. Make this a forced conversion
to remove the following sparse warning:

fs/ubifs/journal.c:506:30: warning: incorrect type in assignment (different base types)
fs/ubifs/journal.c:506:30:    expected restricted __le32 [usertype] cookie
fs/ubifs/journal.c:506:30:    got unsigned int
Signed-off-by: NBen Dooks <ben.dooks@codethink.co.uk>
Signed-off-by: NRichard Weinberger <richard@nod.at>

fs/ubifs/journal.c

@@ -503,7 +503,7 @@ static void mark_inode_clean(struct ubifs_info *c, struct ubifs_inode *ui)
 static void set_dent_cookie(struct ubifs_info *c, struct ubifs_dent_node *dent)
 {
 	if (c->double_hash)
-		dent->cookie = prandom_u32();
+		dent->cookie = (__force __le32) prandom_u32();
 	else
 		dent->cookie = 0;
 }