staging: wilc1000: fix return type of wilc_send_config_pkt

wilc_send_config_pkt is returned 0 or -ETIMEDOUT according to return
value of wilc_wlan_cfg_set or wilc_wlan_cfg_set.
It is better to use int type to represent linux standard error code.

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