usb: misc: legousbtower: Fix buffers on stack

commit 942a4873 upstream.

Allocate buffers on HEAP instead of STACK for local structures
that are to be received using usb_control_msg().

Signed-off-by: Maksim Salau <maksim.salau@gmail.com>
Tested-by: Alfredo Rafael Vicente Boix <alviboi@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>