lcd parameter calculate setting

        panel-timing {
            clock-frequency = <145200000>;
            hactive = <1920>;
            vactive = <1080>;

            hfront-porch = <120>;
            hback-porch = <120>;
            hsync-len = <40>;

            vfront-porch = <8>;
            vback-porch = <8>;
            vsync-len = <4>;

            hsync-active = <0>;
            vsync-active = <0>;
            de-active = <1>;
            pixelclk-active = <0>;
        };

1. clock-frequency
   PeriodHSPeriodVSrate
2. x+y+z=280
3. x+y+z=20