!8207 drm/msm: Fix null pointer dereference on pointer edp

Merge Pull Request from: @ci-robot 
 
PR sync from: Liu Chuang <liuchuang40@huawei.com>
https://mailweb.openeuler.org/hyperkitty/list/kernel@openeuler.org/message/32MQY5JFVQQ5SXWGKRSM5QK6SGJUKJTO/ 
 
https://gitee.com/src-openeuler/kernel/issues/I9RB7E 
 
Link:https://gitee.com/openeuler/kernel/pulls/8207

 

Reviewed-by: Liu YongQiang <liuyongqiang13@huawei.com>
Signed-off-by: Zhang Changzhong <zhangchangzhong@huawei.com>