USB: whiteheat: fix memory leak in error path

commit c129197c99550d356cf5f69b046994dd53cd1b9d upstream.

Make sure command buffer is deallocated in case of errors during attach.

Signed-off-by: Johan Hovold <jhovold@gmail.com>
Cc: <support@connecttech.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>