arm64: dts: sdm845: Add minimal dts/dtsi files for sdm845 SoC and MTP

Add a skeletal sdm845 SoC dtsi and MTP board dts/dtsi files

Signed-off-by: Rajendra Nayak <rnayak@codeaurora.org>
Reviewed-by: Doug Anderson <dianders@chromium.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Andy Gross <andy.gross@linaro.org>