power: supply: axp288_charger: Fix missing mutex_init()

The driver allocates the mutex but not initialize it.
Use mutex_init() on it to initialize it correctly.

Fixes: ed229454 ("power: supply: axp288-charger: Optimize register reading method")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>

drivers/power/supply/axp288_charger.c

@@ -865,6 +865,7 @@ static int axp288_charger_probe(struct platform_device *pdev)
 	if (!info)
 		return -ENOMEM;
 
+	mutex_init(&info->lock);
 	info->pdev = pdev;
 	info->regmap = axp20x->regmap;
 	info->regmap_irqc = axp20x->regmap_irqc;