Merge changes from topic "allwinner_pmic" into integration

* changes:
  allwinner: Convert AXP803 regulator setup code into a driver
  allwinner: a64: power: Use fdt_for_each_subnode
  allwinner: a64: power: Remove obsolete register check
  allwinner: a64: power: Remove duplicate DT check
  allwinner: Build PMIC bus drivers only in BL31
  allwinner: a64: power: Make sunxi_turn_off_soc static
  allwinner: Merge duplicate code in sunxi_power_down
  allwinner: Clean up PMIC-related error handling
  allwinner: Synchronize PMIC enumerations
  allwinner: Enable clock before resetting I2C/RSB