z3fold: remove unused attribute for release_z3fold_page

Since commit dcf5aedb ("z3fold: stricter locking and more careful
reclaim"), release_z3fold_page() is used again.  So we can drop the
unused attribute safely.

Link: https://lkml.kernel.org/r/20210120084008.58432-1-linmiaohe@huawei.comSigned-off-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Vitaly Wool <vitaly.wool@konsulko.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/z3fold.c

@@ -541,8 +541,7 @@ static void __release_z3fold_page(struct z3fold_header *zhdr, bool locked)
 	spin_unlock(&pool->stale_lock);
 }
 
-static void __attribute__((__unused__))
-			release_z3fold_page(struct kref *ref)
+static void release_z3fold_page(struct kref *ref)
 {
 	struct z3fold_header *zhdr = container_of(ref, struct z3fold_header,
 						refcount);