staging: wilc1000: fix return type of host_int_set_mac_chnl_num

This patch changes return type of host_int_set_mac_chnl_num from s32 to
int. s32Error gets return value from wilc_mq_send function that
has return type of int. It should be changed return type of
host_int_set_mac_chnl_num function by int as well as data type of
s32Error.

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