Add Display SubSystem (DSS) DT node for the AM62A7 SoC.

The DSS supports one each of video pipeline (vid) and video-lite
pipeline (vidl1). The video port 1 (vp1) is tied-off in AM62A SoC, but
the pipeline remains active. The video port 2 (vp2) outputs the DPI
signals. Both the video ports are connected to the pipelines via 2
identical overlay managers (ovr1 and ovr2).
Signed-off-by: Aradhya Bhatia <a-bhatia1@ti.com>
Link: https://lore.kernel.org/r/20240201125452.1920623-2-a-bhatia1@ti.comSigned-off-by: Vignesh Raghavendra <vigneshr@ti.com>