Second set of IIO fix for the 5.3 cycle.
* adf4371
- Calculation of the value to program to control the output frequency
was incorrect.
* max9611
- Fix temperature reading in probe. A recent fix for a wrong mask
meant this code was looked at afresh. A second bug became obvious
in which the return value was used inplace of the desired register
value. This had no visible effect other than a communication test
not actually testing the communications.