net: hns3: void array out of bound when loop tnl_num

When query reg inf of SSU, it loops tnl_num times. However, tnl_num comes
from hardware and the length of array is a fixed value. To void array out
of bound, make sure the loop time is not greater than the length of array

Signed-off-by: Peiyang Wang <wangpeiyang1@huawei.com>
Signed-off-by: Jijie Shao <shaojijie@huawei.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>