arm64: dts: qcom: qcs615: Add IMEM and PIL info region

Add a simple-mfd representing IMEM on QCS615 and define the PIL
relocation info region as its child. The PIL region in IMEM is used to
communicate load addresses of remoteproc to post mortem debug tools, so
that these tools can collect ramdumps.

Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
Signed-off-by: Lijuan Gao <quic_lijuang@quicinc.com>
Link: https://lore.kernel.org/r/20250526-add_qcs615_remoteproc_support-v4-4-06a7d8bed0b5@quicinc.com


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