arm64: dts: qcom: Add PURWA-IOT-SOM platform

arm64: dts: qcom: Add PURWA-IOT-SOM platform

The PURWA-IOT-SOM is a compact computing module that integrates a System
on Chip (SoC) — specifically the x1p42100 — along with essential
components optimized for IoT applications. It is designed to be mounted on
carrier boards, enabling the development of complete embedded systems.

Purwa uses a slightly different Iris HW revision (8.1.2 on Hamoa, 8.1.11 on
Purwa). Support will be added later.

Make the following peripherals on the SOM enabled:
- Regulators on the SOM
- Reserved memory regions
- PCIe3, PCIe4, PCIe5, PCIe6a
- USB0 through USB6 and their PHYs
- ADSP, CDSP
- Graphic

Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
Signed-off-by: Yijie Yang <yijie.yang@oss.qualcomm.com>
Reviewed-by: Abel Vesa <abel.vesa@oss.qualcomm.com>
Link: https://lore.kernel.org/r/20260202073555.1345260-3-yijie.yang@oss.qualcomm.com
Signed-off-by: Bjorn Andersson <andersson@kernel.org>