HID: udraw-ps3: Add support for the uDraw tablet for PS3
This adds support for the THQ uDraw tablet for the PS3, as
4 separate device nodes, so that user-space can easily consume
events coming from the hardware.
Note that the touchpad two-finger support is fairly unreliable,
and a right-click can only be achieved with a two-finger tap
with the two fingers slightly apart (about 1cm should be enough).