ethernet: smsc: remove unnecessary (void*) conversions

No need cast (voidd*) to (struct smsc911x_data *) or
(struct smsc9420_pdata *).

Signed-off-by: Wu Yunchuan <yunchuan@nfschina.com>
Link: https://lore.kernel.org/r/20230717031204.54912-1-yunchuan@nfschina.com


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