!4806 v2 media: pvrusb2: fix use after free on context disconnection

Merge Pull Request from: @ci-robot 
 
PR sync from: Guan Jing <guanjing6@huawei.com>
https://mailweb.openeuler.org/hyperkitty/list/kernel@openeuler.org/message/TJNB5GECQCFTKVIUE5JDOMESDCWAGT2Q/ 
 
https://gitee.com/src-openeuler/kernel/issues/I932VV 
 
Link:https://gitee.com/openeuler/kernel/pulls/4806

 

Reviewed-by: Zhang Changzhong <zhangchangzhong@huawei.com>
Signed-off-by: Zhang Changzhong <zhangchangzhong@huawei.com>