arm64: dts: qcom: msm8916: Add unit name for /soc node

This fixes the following warning when building with W=1:
Warning (unit_address_vs_reg): /soc: node has a reg or ranges property,
but no unit name

Signed-off-by: Stephan Gerhold <stephan@gerhold.net>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20210921152120.6710-1-stephan@gerhold.net