ARM: dts: qcom: sdx65: Add support for APCS block

The APCS block on SDX65 acts as a mailbox controller and also provides
clock output for the Cortex A7 CPU.

Signed-off-by: Rohit Agarwal <quic_rohiagar@quicinc.com>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/1645505785-2271-5-git-send-email-quic_rohiagar@quicinc.com