!3504 net: hns3: fix kernel crash when 1588 is received on HIP08 devices

Merge Pull Request from: @svishen 
 
This pull request fix kernel crash when 1588 is received on HIP08 devices

The HIP08 devices does not register the ptp devices, so the
hdev->ptp is NULL, but the hardware can receive 1588 messages,
and set the HNS3_RXD_TS_VLD_B bit, so, if match this case, the
access of hdev->ptp->flags will cause a kernel crash.

issue:
https://gitee.com/openeuler/kernel/issues/I8QB9J 
 
Link:https://gitee.com/openeuler/kernel/pulls/3504

 

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