arm64: dts: qcom: msm8996: 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/20230420063610.11068-4-krzysztof.kozlowski@linaro.org

arch/arm64/boot/dts/qcom/msm8996.dtsi

@@ -604,7 +604,7 @@ slpi_smp2p_in: slave-kernel {
 		};
 	};
 
-	soc: soc {
+	soc: soc@0 {
 		#address-cells = <1>;
 		#size-cells = <1>;
 		ranges = <0 0 0 0xffffffff>;