ARM: dts: msm: Add qcom,aop-ddr-msgs node for sm8150

Add the qcom,aop-ddr-msgs device tree node for
transmission of DDR speed messages to AOP during device
reboot for sm8150.

Change-Id: I076d148d06cddecad133658fb840f3440866a44b
Signed-off-by: Isaac J. Manjarres <isaacm@codeaurora.org>