!928 hikey9xx: Fixed incorrect use of kfree to free sreg

Merge Pull Request from: @ci-robot 
 
PR sync from:  ZhaoLong Wang <wangzhaolong1@huawei.com>
 https://mailweb.openeuler.org/hyperkitty/list/kernel@openeuler.org/thread/TB3Q7BQ6ZAGBRI7WS6JPCAF77IWURUIW/ 
 
 
Link:https://gitee.com/openeuler/kernel/pulls/928 

Reviewed-by: zhangyi (F) <yi.zhang@huawei.com> 
Reviewed-by: Jialin Zhang <zhangjialin11@huawei.com> 
Signed-off-by: Jialin Zhang <zhangjialin11@huawei.com> 

drivers/staging/hikey9xx/hi6421v600-regulator.c

@@ -452,7 +452,7 @@ static int hi6421_spmi_regulator_remove(struct platform_device *pdev)
 	if (rdev->desc->volt_table)
 		devm_kfree(&pdev->dev, (unsigned int *)rdev->desc->volt_table);
 
-	kfree(sreg);
+	devm_kfree(&pdev->dev, sreg);
 
 	return 0;
 }