wifi: wilc1000: cleanup struct wilc_conn_info

Remove set but otherwise unused 'ch' member of 'struct wilc_conn_info'
and avoid typeless 'void *' pointers in '(*conn_result)()' callback.
Likewise for 'wilc_parse_join_bss_param()'. Compile tested only.

Signed-off-by: Dmitry Antipov <dmantipov@yandex.ru>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20231031171330.70399-1-dmantipov@yandex.ru