arm64: dts: qcom: Add base SM8450 DTSI

This add based DTSI for SM8450 SoC and includes base description of
CPUs, GCC, RPMHCC, UART, interuupt-controller which helps to boot to
shell with console on boards with this SoC
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Reviewed-by: Konrad Dybcio <konrad.dybcio@somainline.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20211215043440.605624-2-vkoul@kernel.org