arm64: dts: qcom: sm8350: Add fastrpc nodes

Add fastrpc nodes for sDSP, cDSP, and aDSP.

Signed-off-by: Ola Jeppsson <ola@snap.com>
Acked-by: Heinrich Fink <hfink@snap.com>
Acked-by: Olivier Schonken <oschonken@snapchat.com>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20211018085017.1549494-1-ola@snap.com