arm64: dts: qcom: qcs404: add prng-ee node

RNG hardware in QCS404 features (Execution Environment) EE for
HLOS to use, add the node for prng-ee for QCS404.

Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Andy Gross <andy.gross@linaro.org>