ARM: dts: qcom: mdm9615: add missing PMIC GPIO reg

'reg' property is required in SSBI children:
  qcom-mdm9615-wp8548-mangoh-green.dtb: gpio@150: 'reg' is a required property

Fixes: 2c5e5965 ("ARM: dts: Add MDM9615 dtsi")
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20220507194913.261121-11-krzysztof.kozlowski@linaro.org