regulator: Updates for v4.3

The biggest changes in the core this time around have been some
refactorings that move us towards being able to drop the list of
regulators maintained by the core and instead just use the driver model
list maintained for the class devices for regulators which will make the
code smaller and avoid some potential bugs.  Otherwise another fairly
quiet release for the regulator API, highlights include:

 - A new API for setting voltages based on a minimum, target, maximum
   triplet.
 - Support for continuous voltage ranges rather than tables of explicit
   steps in the PWM regulator, requiring less explicit configuration.
 - New driver support for Dialog DA9215, Maxim 77843, Mediatek MT6311
   and Qualcomm RPM.
Merge remote-tracking branch 'regulator/topic/tps6586x' into regulator-next