dt-bindings: msm: dsi-controller-main: Add compatible strings for every current SoC

Currently we do not differentiate between the various users of the
qcom,mdss-dsi-ctrl. The driver is flexible enough to operate from one
compatible string but, the hardware does have some significant differences
in the number of clocks.

To facilitate documenting the clocks add the following compatible strings

- qcom,apq8064-dsi-ctrl
- qcom,msm8916-dsi-ctrl
- qcom,msm8974-dsi-ctrl
- qcom,msm8996-dsi-ctrl
- qcom,sc7180-dsi-ctrl
- qcom,sc7280-dsi-ctrl
- qcom,sdm630-dsi-ctrl
- qcom,sdm660-dsi-ctrl
- qcom,sdm845-dsi-ctrl
- qcom,sm8250-dsi-ctrl

Each SoC dtsi should declare "qcom,socname-dsi-ctrl", "qcom,mdss-dsi-ctrl";

Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>