arm64: dts: qcom: sdm845: Add SoC compatible to MTP

Add missing SoC compatible to SDM845 MTP board file.

Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
Reviewed-by: Amit Kucheria <amit.kucheria@linaro.org>
Signed-off-by: Sibi Sankar <sibis@codeaurora.org>
Link: https://lore.kernel.org/r/20200504202243.5476-2-sibis@codeaurora.org


Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>