net: hns: Remove unnecessary (void*) conversions

No need cast (void*) to (struct hns_mdio_device *).

Signed-off-by: Wu Yunchuan <yunchuan@nfschina.com>
Reviewed-by: Hao Lan <lanhao@huawei.com>
Link: https://lore.kernel.org/r/20230717031137.54639-1-yunchuan@nfschina.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>