arm64: dts: qcom: msm8916: Add debug unit

Add debug unit on Qualcomm msm8916 based platforms, including the
DragonBoard 410c board.

Signed-off-by: Leo Yan <leo.yan@linaro.org>
Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Acked-by: Andy Gross <andy.gross@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>