staging: wilc1000: clear_shadow_scan: remove unused argument

This patch removes pUserVoid that is first argument of
clear_shadow_scan function because it is not used in this function.
Remove argument in the function call also.

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