arm64: dts: qcom: monaco: Add EL2 overlay

arm64: dts: qcom: monaco: Add EL2 overlay

All the Monaco IOT variants boards are using Gunyah hypervisor which
means that, so far, Linux-based OS could only boot in EL1 on those
devices.  However, it is possible for us to boot Linux at EL2 on these
devices [1].

When running under Gunyah, the remote processor firmware IOMMU streams
are controlled by Gunyah. However, without Gunyah, the IOMMU is managed
by the consumer of this DeviceTree. Therefore, describe the firmware
streams for each remote processor.

Add a EL2-specific DT overlay and apply it to Monaco IOT variant
devices to create -el2.dtb for each of them alongside "normal" dtb.

[1]
https://docs.qualcomm.com/bundle/publicresource/topics/80-70020-4/boot-developer-touchpoints.html#uefi

Signed-off-by: Mukesh Ojha <mukesh.ojha@oss.qualcomm.com>
Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
Link: https://lore.kernel.org/r/20260127-talos-el2-overlay-v2-2-b6a2266532c4@oss.qualcomm.com
Signed-off-by: Bjorn Andersson <andersson@kernel.org>