staging: wilc1000: wlan_deinitialize_threads: change argument and use wilc

This patch changes function parameter type struct wilc with struct net_device
and use netdev private data member wilc instead of g_linux_wlan.

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