mm/zsmalloc: use obj_index to keep consistent with others

	struct page *d_page;

	 /* Starting object index within @s_page which used for live object

	  * in the subpage. */

	int index;

	int obj_idx;

};

static int migrate_zspage(struct zs_pool *pool, struct size_class *class,

	unsigned long handle;

	struct page *s_page = cc->s_page;

	struct page *d_page = cc->d_page;

	unsigned long index = cc->index;

	int obj_idx = cc->obj_idx;

	int ret = 0;

	while (1) {

		handle = find_alloced_obj(class, s_page, index);

		handle = find_alloced_obj(class, s_page, obj_idx);

		if (!handle) {

			s_page = get_next_page(s_page);

			if (!s_page)

				break;

			index = 0;

			obj_idx = 0;

			continue;

		}

		used_obj = handle_to_obj(handle);

		free_obj = obj_malloc(class, get_zspage(d_page), handle);

		zs_object_copy(class, free_obj, used_obj);

		index++;

		obj_idx++;

		/*

		 * record_obj updates handle's value to free_obj and it will

		 * invalidate lock bit(ie, HANDLE_PIN_BIT) of handle, which

	/* Remember last position in this iteration */

	cc->s_page = s_page;

	cc->index = index;

	cc->obj_idx = obj_idx;

	return ret;

}

		if (!zs_can_compact(class))

			break;

		cc.index = 0;

		cc.obj_idx = 0;

		cc.s_page = get_first_page(src_zspage);

		while ((dst_zspage = isolate_zspage(class, false))) {