arm64: dts: qcom: sc7180: Add IMEM and pil info regions

Add IMEM and pil info DT nodes for SC7180 SoC which will help in the
post-mortem debug.

Signed-off-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
[bjorn: Dropped dload-mode subnode, as no agreement was reached on this binding]
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/39064a2db95ccc2cb5eef003569bef2de651c8ed.1628757036.git.saiprakash.ranjan@codeaurora.org