arm64: dts: qcom: msm8916: Drop underscore in node name

Using underscores in device tree nodes is not very common.
Additionally, the _region suffix in "smem_region@..." is not really
useful since it's obvious that it describes a reserved memory region.

Signed-off-by: Stephan Gerhold <stephan@gerhold.net>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20210921152120.6710-2-stephan@gerhold.net