staging: wilc1000: handle_set_mac_address: change data type of result

result variable gets value from wilc_send_config_pkt that has return
value of int. This patch changes data type of result variable to int.

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