ARM: dts: qcom: sdx55: Add support for APCS block

The APCS block on SDX55 acts as a mailbox controller and also provides
clock output for the Cortex A7 CPU.

Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/20210408170457.91409-3-manivannan.sadhasivam@linaro.org


Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>