power: supply: ab8500: fix leaked of_node refs in ab8500_bm_of_probe

The call to of_parse_phandle returns a node pointer with refcount
incremented thus it must be explicitly decremented after the last
usage.

492 int ab8500_bm_of_probe(struct device *dev,
493                        struct device_node *np,
494                        struct abx500_bm_data *bm)
495 {
496         const struct batres_vs_temp *tmp_batres_tbl;
497         struct device_node *battery_node;
    ...
501         /* get phandle to 'battery-info' node */
502         battery_node = of_parse_phandle(np, "battery", 0);
    ...
509         if (!btech) {
510                 dev_warn(dev, "missing property battery-name/type\n");
511                 return -EINVAL;    ---> leaked here
512         }
    ...
540         of_node_put(battery_node);   ---> released here
541
542         return 0;
543 }

Detected by coccinelle with the following warnings:
./drivers/power/supply/ab8500_bmdata.c:511:2-8: ERROR: missing of_node_put; acquired a node pointer with refcount incremented on line 502, but without a corresponding object release within this function.

Signed-off-by: Wen Yang <wen.yang99@zte.com.cn>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>