Don’t disable trackpad if only mouse available is touchscreen

[usr-sse2]

VoodooI2C/VoodooI2C#147

[vit9696]

@usr-sse2 can you clarify why is that an error? I am afraid that we may not even have control over this, as it should be decided on macOS side, not on the driver side. I also believe that the behaviour is the same on iMacs with Magic Trackpad.

[usr-sse2]

@vit9696 No, the control is on our side. See ApplePS2SynapticsTouchPad::notificationHIDAttachedHandlerGated. (But it may be the case that currently both we and macOS are disabling the trackpad – I haven't checked it. But when VoodooPS2 worked not through MT2 simulation, the system didn't control it).

This is an error because the semantics of this setting is to disable built-in pointing devices when an external pointing device is connected. Macs don't have built-in touchscreens, so for Macs it's all OK. Lenovo Yoga has a built-in touchscreen, so the checkbox becomes useless because it just disables the trackpad always.

[usr-sse2]

I checked, we are already checking the device class, and for touchscreen we're not disabling the trackpad, so macOS does it. Still the code in VoodooPS2 shouldn't be removed, because it also affects physical buttons and trackpoint, which are sent in bypass of MT2 simulator.