m5602 - gspca conversion

So, after submitting the m5602 driver mainline I got some suggestions to port to the gspca framework. Grudgingly, I'm now in the process of doing so.
Fortunately it turned out to be much easier than I ever expected.
Unfortunately every sensor needs to be converted which involves lots of mechanical typing. I expect to be done with the conversion quite soon which should render the driver ready for upstream!