ARM: dts: qcom: pm8941: fix iadc node

The spmi-pmic bindings require the iadc node to be named just 'adc'.

Reviewed-by: Konrad Dybcio <konrad.dybcio@somainline.org>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Signed-off-by: Luca Weiss <luca@z3ntu.xyz>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20221031182456.952648-2-luca@z3ntu.xyz