dt-bindings: display/msm: dsi-controller-main: Add SM7150

Add the DSI host found on SM7150.

Signed-off-by: Danila Tikhonov <danila@jiaxyga.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/601231/


Signed-off-by: Rob Clark <robdclark@chromium.org>