arm64: dts: qcom: sa8295p-adp: add fallback compatible to PMIC GPIOs

Bindings require all PMIC GPIO nodes to have two compatibles - specific
followed by SPMI or SSBI fallback:

  qcom/sa8295p-adp.dtb: pmic@8: gpio@c000:compatible: ['qcom,pm8150-gpio'] is too short

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20220908081050.29751-4-krzysztof.kozlowski@linaro.org