staging: wilc1000: wilc_wlan_cfg_init: changes unused argument

This patch changes the argument of the wilc_wlan_cfg_init function,
wilc_debug to void type because wilc_debug function is not used any more.
In addition, finally removes wilc_debug and related variables.

Signed-off-by: Leo Kim <leo.kim@atmel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>