power: supply: ab8500_fg: silence uninitialized variable warnings

If kstrtoul() fails then we print "charge_full" when it's uninitialized.
The debug printk doesn't add anything so I deleted it and cleaned these
two functions up a bit.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>

drivers/power/supply/ab8500_fg.c

@@ -2433,17 +2433,14 @@ static ssize_t charge_full_store(struct ab8500_fg *di, const char *buf,
 				 size_t count)
 {
 	unsigned long charge_full;
-	ssize_t ret;
+	int ret;
 
 	ret = kstrtoul(buf, 10, &charge_full);
+	if (ret)
+		return ret;
 
-	dev_dbg(di->dev, "Ret %zd charge_full %lu", ret, charge_full);
-
-	if (!ret) {
 	di->bat_cap.max_mah = (int) charge_full;
-		ret = count;
-	}
-	return ret;
+	return count;
 }
 
 static ssize_t charge_now_show(struct ab8500_fg *di, char *buf)
@@ -2455,20 +2452,16 @@ static ssize_t charge_now_store(struct ab8500_fg *di, const char *buf,
 				 size_t count)
 {
 	unsigned long charge_now;
-	ssize_t ret;
+	int ret;
 
 	ret = kstrtoul(buf, 10, &charge_now);
+	if (ret)
+		return ret;
 
-	dev_dbg(di->dev, "Ret %zd charge_now %lu was %d",
-		ret, charge_now, di->bat_cap.prev_mah);
-
-	if (!ret) {
 	di->bat_cap.user_mah = (int) charge_now;
 	di->flags.user_cap = true;
-		ret = count;
 	queue_delayed_work(di->fg_wq, &di->fg_periodic_work, 0);
-	}
-	return ret;
+	return count;
 }
 
 static struct ab8500_fg_sysfs_entry charge_full_attr =