arm64: dts: qcom: add QCS615 platform

Add initial DTSI for QCS615 SoC.

Features added in this revision:
- CPUs with PSCI idle states
- Interrupt-controller with PDC wakeup support
- Timers, TCSR Clock Controllers
- Reserved Shared memory
- QFPROM
- TLMM
- Watchdog
- RPMH controller
- Sleep stats driver
- Rpmhpd power controller
- Interconnect
- GCC and Rpmhcc
- QUP with Uart serial support

Written with help from Tingguo Cheng (added rpmhpd power controller nodes)
Taniya Das (added clocks nodes), and Raviteja Laggyshetty (added
interconnect nodes).

Signed-off-by: Lijuan Gao <quic_lijuang@quicinc.com>
Link: https://lore.kernel.org/r/20241104-add_initial_support_for_qcs615-v5-3-9dde8d7b80b0@quicinc.com


Signed-off-by: Bjorn Andersson <andersson@kernel.org>