wm97xx_battery: Fix error return code

Initialize return variable before exiting on an error path.

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 <Julia.Lawall@lip6.fr>
Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org>

drivers/power/wm97xx_battery.c

@@ -212,8 +212,10 @@ static int __devinit wm97xx_bat_probe(struct platform_device *dev)
 		props++;	/* POWER_SUPPLY_PROP_VOLTAGE_MIN */
 
 	prop = kzalloc(props * sizeof(*prop), GFP_KERNEL);
-	if (!prop)
+	if (!prop) {
+		ret = -ENOMEM;
 		goto err3;
+	}
 
 	prop[i++] = POWER_SUPPLY_PROP_PRESENT;
 	if (pdata->charge_gpio >= 0)