staging: vt6655: Fixed C99 // comment errors in wpactl.c

The following patch fixes the checkpatch.pl warning:
ERROR: do not use C99 // comments

Signed-off-by: Esra Altintas <es.altintas@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>