dt-bindings: soc: qcom: Add dt-bindings support for DCC

DCC is a hardware engine to write and read registers for system debug.

Change-Id: I17b40bbc9956af8d72a5123472b9a351c7b9e4d3
Signed-off-by: Mulu He <muluhe@codeaurora.org>
Signed-off-by: Tingwei Zhang <tingwei@codeaurora.org>