regulator: qcom_pm8008: change reg property format from u16 to u32

Use of_property_read_u32() instead of of_property_read_u16() to
read the "reg" property of each PM8008 regulator device tree node.
This allows the "reg" property value to be specified in device
tree without the parameter "/bits/ 16".  This in turn avoids
device tree compilation warnings like this one:

arch/arm64/boot/dts/vendor/qcom/lahaina-pmic-overlay.dtsi:68.5-30:
Warning (reg_format):
  /soc/i2c@a94000/pm8008i@8/qcom,pm8008i-regulator/regulator@4000:reg:
  property has invalid length (2 bytes)
  (#address-cells == 1, #size-cells == 0)

Change-Id: I69d7af28339abf3b7ed1365ccfc9343958f944da
Signed-off-by: David Collins <collinsd@codeaurora.org>