staging: wilc1000: remove unnecesary type cast of bss_type

There is no need to use type cast of bss_type because
hif_drv->cfg_values.bss_type is u8.

Signed-off-by: Chaehyun Lim <chaehyun.lim@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>