power: supply: check if calc_soc succeeded in pm860x_init_battery

clang static analysis flags this error

88pm860x_battery.c:522:19: warning: Assigned value is
  garbage or undefined [core.uninitialized.Assign]
                info->start_soc = soc;
                                ^ ~~~
soc is set by calling calc_soc.
But calc_soc can return without setting soc.

So check the return status and bail similarly to other
checks in pm860x_init_battery and initialize soc to
silence the warning.

Fixes: a830d28b ("power_supply: Enable battery-charger for 88pm860x")
Signed-off-by: Tom Rix <trix@redhat.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>

drivers/power/supply/88pm860x_battery.c

@@ -433,7 +433,7 @@ static void pm860x_init_battery(struct pm860x_battery_info *info)
 	int ret;
 	int data;
 	int bat_remove;
-	int soc;
+	int soc = 0;
 
 	/* measure enable on GPADC1 */
 	data = MEAS1_GP1;
@@ -496,7 +496,9 @@ static void pm860x_init_battery(struct pm860x_battery_info *info)
 	}
 	mutex_unlock(&info->lock);
 
-	calc_soc(info, OCV_MODE_ACTIVE, &soc);
+	ret = calc_soc(info, OCV_MODE_ACTIVE, &soc);
+	if (ret < 0)
+		goto out;
 
 	data = pm860x_reg_read(info->i2c, PM8607_POWER_UP_LOG);
 	bat_remove = data & BAT_WU_LOG;