net: hns3: change hnae3_register_ae_dev() to int

hnae3_register_ae_dev() may fail, and it should return a error code
to its caller, so change hnae3_register_ae_dev() return type to int.

Also, when hnae3_register_ae_dev() return error, hns3_probe() should
do some error handling and return the error code.

Signed-off-by: Huazhong Tan <tanhuazhong@huawei.com>
Signed-off-by: Peng Li <lipeng321@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>