arm64: dts: qcom: msm8998: add unit address to soc node

"soc" node is supposed to have unit address:

  Warning (unit_address_vs_reg): /soc: node has a reg or ranges property, but no unit name

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20230420063610.11068-5-krzysztof.kozlowski@linaro.org