ARM: dts: msm: Add cdsp rpmsg entry

CDSPRM module relies on the rpmsg node to create a communication
channel with CDSP. The node also carries information for Cx i-peak
limit management, CPU QoS voting, HVX, CDSP thermal mitigation
frameworks.

CDSPRM module implements a RPMSG interface to communicate with CDSP
while providing a way for CDSP to vote for CPU L3 clock, CPU QoS to
benefit CDSP applications performance. The module also implements
an interface with NPU for Cx i-peak limit management and registers
cooling devices for CDSP and HVX thermal mitigation.

Change-Id: I914b10fa877c6d890b5cecb5c931dc017ede7f6f
Acked-by: Sreekanth Gande <sgande@qti.qualcomm.com>