hello Dušan,
I don't have those drivers installed right now (I recently re-installed fresh Win10), but I'm pretty sure that you can see in Control Panel (Programs & Features) what driver you have installed (if you sort installed software by name, Yamaha's stuff will be listed at the end of list).
But then, if you're not sure, just install MIDI driver -there's no harm if Steinberg driver is already installed.
Greetings,
Bogdan