!1779 nvme-pci: clear the prp2 field when not used

Merge Pull Request from: @ci-robot 
 
PR sync from: Yong Hu <yong.hu@windriver.com>
https://mailweb.openeuler.org/hyperkitty/list/kernel@openeuler.org/message/SMDLQ6YOY254PJZ4U4FIGFZYT3HIREFQ/ 
 
https://gitee.com/openeuler/kernel/issues/I7PZZC 
 
Link:https://gitee.com/openeuler/kernel/pulls/1779

 

Reviewed-by: Jialin Zhang <zhangjialin11@huawei.com>
Signed-off-by: Jialin Zhang <zhangjialin11@huawei.com>