6th set of IIO new driver support, clean up and fixes for the 3.8 cycle (possibly wait until 3.9 cycle given timing). Here we have * the cleanup and move out of staging of ad7793. * addition support for additional parts to ad7793. * a basic new driver for TI ADC081C021/027 * 4 little fixes for the recent addition of ad16136 and ad16480. So some nice work with nothing controversial or anything that will effect stuff outside the drivers in question.