arm64: dts: qcom: sc7280: Add IPCC for SC7280 SoC

Add the IPCC DT node which is used to send and receive IPC
signals with remoteprocs for SC7280 SoC.

Cc: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Cc: Jassi Brar <jaswinder.singh@linaro.org>
Signed-off-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Link: https://lore.kernel.org/r/8374f407386209d2e7891763de3fa2450a14ad60.1615832893.git.saiprakash.ranjan@codeaurora.org


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