net: hisilicon: fix hsn3_ethtool kernel-doc warnings

Fix kernel-doc warnings and spacing in hns3_ethtool.c:

hns3_ethtool.c:246: warning: No description found for return value of 'hns3_lp_run_test'
hns3_ethtool.c:408: warning: expecting prototype for hns3_nic_self_test(). Prototype was for hns3_self_test() instead

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reported-by: kernel test robot <lkp@intel.com>
Cc: Peng Li <lipeng321@huawei.com>
Cc: Guangbin Huang <huangguangbin2@huawei.com>
Cc: Yisen Zhuang <yisen.zhuang@huawei.com>
Cc: Salil Mehta <salil.mehta@huawei.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>