Add basic support for Nokia N9

Created by: pavelmachek

Filip Matijević did all the work here, I'm just attempting to merge it (with his permission).

N9 has pretty good mainline support, and it is being improved, so it is good target. OTOH it does not have a u-SD card slot, and battery is not removable, which makes it tricky. Currently, it is usable with root mounted over NFS over USB, including working xfce4.