arm64: dts: qcom: sm6350: Add PRNG node

Add a node for the PRNG to enable hw-accelerated pseudo-random number
generation.

Signed-off-by: Konrad Dybcio <konrad.dybcio@somainline.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20210923162204.21752-12-konrad.dybcio@somainline.org