Only add USB tablet if supported
Submitted by Zeeshan Ali (Khattak)
Apparently, some operating systems (Solaris 11 at least) don't like the USB tablet and mouse cursor won't move on them if USB tablet is included in the domain configuration. Let's only add this device if its supported by the OS.
We'll first have to add the USB tablet to known supporting OSs first in libosinfo's database before making addition of USB tablet device conditional.