[Device] Support using only throttle (or stick) on HOTAS setups

[Athanasius]

I have a Saitek (yes, earlier than Logitech's buyout) X-56 but have only been using the throttle of it for years now. Generating a bindings build for my setup thinks I'm also using the stick.

It would be good if you took into account all three variants (both, stick only, throttle only) that are possible with such devices. I realise this will entail fiddling with extra images etc :) .