regulator: Updates for v5.1 The bulk of the standout changes in this release are cleanups, with the core work being a combination of factoring out common code into helpers and the completion of the conversion of the core to use GPIO descriptors. - Addition of helper functions for current limits and conversion of drivers to use them by Axel Lin. - Lots and lots of cleanups from Axel Lin. - Conversion of the core to use GPIO descriptors rather than numbers by Linus Walleij. - New drivers for Maxim MAX77650 and ROHM BD70528.