arm64: dts: qcom: talos: Add EL2 overlay

arm64: dts: qcom: talos: Add EL2 overlay

All the existing variants Talos 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 Talos 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

Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
Signed-off-by: Mukesh Ojha <mukesh.ojha@oss.qualcomm.com>
Link: https://lore.kernel.org/r/20260127-talos-el2-overlay-v2-3-b6a2266532c4@oss.qualcomm.com
Signed-off-by: Bjorn Andersson <andersson@kernel.org>