arm64: dts: qcom: sc7280: Add nodes to boot modem

Add miscellaneous nodes to boot the modem and support post-mortem debug
on SC7280 SoCs.

Signed-off-by: Sibi Sankar <sibis@codeaurora.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/1631886935-14691-9-git-send-email-sibis@codeaurora.org