net: hns3: fix dereference of ae_dev before it is null checked

Pointer ae_dev is null checked however, prior to that it is dereferenced
when assigned pointer ops. Fix this by assigning pointer ops after ae_dev
has been null checked.

Addresses-Coverity: ("Dereference before null check")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: David S. Miller <davem@davemloft.net>