staging: vt6656: iwctl_giwaplist/device_ioctl : use off stack buffers.

Calls ioctl SIOCGIWAPLIST use off stack buffers.

clears up warning messages.
main_usb.c:2015:1: warning: the frame size of 1888 bytes is larger than 1024 bytes [-Wframe-larger-than=]
iwctl.c:683:1: warning: the frame size of 1280 bytes is larger than 1024 bytes [-Wframe-larger-than=]

Signed-off-by: Malcolm Priestley <tvboxspy@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>