staging: wilc1000: remove unused typedef wilc_wlan_cfg_func_t

This patch removes unused typedef wilc_wlan_cfg_func_t of wilc_wlan.h.

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