clk: qcom: dispcc: Add support for display port clocks

SDM845 dispcc supports RCG and CBCRs for display port, so add support for
the same.

Signed-off-by: Taniya Das <tdas@codeaurora.org>
Link: https://lkml.kernel.org/r/20190731182713.8123-3-tdas@codeaurora.org
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

dt-bindings: clock: Introduce QCOM Display clock bindings

Add device tree bindings for display clock controller for Qualcomm
Technology Inc's SDM845 SoCs.

Signed-off-by: Taniya Das <tdas@codeaurora.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>