staging: wilc1000: change data type of wid argument in wilc_wlan_cfg_get_val

This patch changes data type of wid argument in wilc_wlan_cfg_get_val
from u32 to u16. It is better to change data type of wid because wid has
one of enum WID_T that is data type of u16. And, there is no need to use
u16 type casting when calling wilc_wlan_cfg_get_wid_value function.

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