net: hns3: add hns3_state_init() to do state initialization

To improve the readability and maintainability, add hns3_state_init() to
initialize the state, and this new function will be used to add more state
initialization in the future.

Signed-off-by: Huazhong Tan <tanhuazhong@huawei.com>
Signed-off-by: Guangbin Huang <huangguangbin2@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>