power_supply: Replace strict_strtoul() with kstrtoul()

The usage of strict_strtoul() is not preferred, because strict_strtoul()
is obsolete. Thus, kstrtoul() should be used.

Signed-off-by: Jingoo Han <[e-mail]>
Reviewed-by: Andy Shevchenko <[e-mail]>
Signed-off-by: Anton Vorontsov <[e-mail]>

drivers/power/ab8500_fg.c

···
 				 size_t count)
 {
 	unsigned long charge_full;
-	ssize_t ret = -EINVAL;
+	ssize_t ret;
 
-	ret = strict_strtoul(buf, 10, &charge_full);
+	ret = kstrtoul(buf, 10, &charge_full);
 
 	dev_dbg(di->dev, "Ret %zd charge_full %lu", ret, charge_full);
 
···
 	unsigned long charge_now;
 	ssize_t ret;
 
-	ret = strict_strtoul(buf, 10, &charge_now);
+	ret = kstrtoul(buf, 10, &charge_now);
 
 	dev_dbg(di->dev, "Ret %zd charge_now %lu was %d",
 		ret, charge_now, di->bat_cap.prev_mah);

drivers/power/pcf50633-charger.c

···
 	unsigned long ma;
 	int ret;
 
-	ret = strict_strtoul(buf, 10, &ma);
+	ret = kstrtoul(buf, 10, &ma);
 	if (ret)
-		return -EINVAL;
+		return ret;
 
 	pcf50633_mbc_usb_curlim_set(mbc->pcf, ma);
 
···
 	if (!mbc->pcf->pdata->charger_reference_current_ma)
 		return -ENODEV;
 
-	ret = strict_strtoul(buf, 10, &ma);
+	ret = kstrtoul(buf, 10, &ma);
 	if (ret)
-		return -EINVAL;
+		return ret;
 
 	mbcc5 = (ma << 8) / mbc->pcf->pdata->charger_reference_current_ma;
 	if (mbcc5 > 255)