!9684 greybus: lights: check return of get_channel_from_mode

Merge Pull Request from: @ci-robot 
 
PR sync from: liwei <liwei728@huawei.com>
https://mailweb.openeuler.org/hyperkitty/list/kernel@openeuler.org/message/7KSNTX4Q3IHU6UWYNDIBC4I3RWZBCUNR/ 
 
https://gitee.com/src-openeuler/kernel/issues/IA7D18 
 
Link:https://gitee.com/openeuler/kernel/pulls/9684

 

Reviewed-by: Wei Li <liwei391@huawei.com>
Reviewed-by: Liu YongQiang <liuyongqiang13@huawei.com>
Signed-off-by: Zhang Changzhong <zhangchangzhong@huawei.com>