arm64: dts: qcom: enable the download mode support

Like any other Qualcomm SoCs, IPQ8074 and IPQ6018 also supports the
download mode to collect the RAM dumps if system crashes, to perform
the post mortem analysis. Add support for the same.

Signed-off-by: Vignesh Viswanathan <quic_viswanat@quicinc.com>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20230526110653.27777-3-quic_viswanat@quicinc.com