arm64: dts: qcom: sdm845: add SLPI remoteproc

Add the SLPI remoteproc to the SDM845 Qualcomm SoC which is responsible
for exposing the sensors connected to the SoC. The SLPI communicates
over GLink edge 'dsps' and is similar to other DSPs e.g. ADSP or CDSP.
This patch allows the SLPI to boot and expose itself over QRTR as
service 400.

Signed-off-by: Dylan Van Assche <me@dylanvanassche.be>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20230406173148.28309-2-me@dylanvanassche.be