dt-bindings: display: ti,am65x-dss: Add am625 dss compatible

The DSS controller on TI's AM625 SoC is an update from that on TI's
AM65X SoC. The former has an additional OLDI TX on its first video port
that helps output cloned video or WUXGA (1920x1200@60fps) resolution
video output over a dual-link mode to reduce the required OLDI clock
output.

The second video port is same from AM65x DSS and it outputs DPI video
data. It can support 2K resolutions @ 60fps, independently.

Add the new controller's compatible and update descriptions.
Signed-off-by: Aradhya Bhatia <a-bhatia1@ti.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230616150900.6617-2-a-bhatia1@ti.com

Documentation/devicetree/bindings/display/ti/ti,am65x-dss.yaml

@@ -12,14 +12,18 @@ maintainers:
   - Tomi Valkeinen <tomi.valkeinen@ti.com>
 
 description: |
-  The AM65x TI Keystone Display SubSystem with two output ports and
-  two video planes. The first video port supports OLDI and the second
-  supports DPI format. The fist plane is full video plane with all
-  features and the second is a "lite plane" without scaling support.
+  The AM625 and AM65x TI Keystone Display SubSystem with two output
+  ports and two video planes. In AM65x DSS, the first video port
+  supports 1 OLDI TX and in AM625 DSS, the first video port output is
+  internally routed to 2 OLDI TXes. The second video port supports DPI
+  format. The first plane is full video plane with all features and the
+  second is a "lite plane" without scaling support.
 
 properties:
   compatible:
-    const: ti,am65x-dss
+    enum:
+      - ti,am625-dss
+      - ti,am65x-dss
 
   reg:
     description:
@@ -80,7 +84,9 @@ properties:
       port@0:
         $ref: /schemas/graph.yaml#/properties/port
         description:
-          The DSS OLDI output port node form video port 1
+          For AM65x DSS, the OLDI output port node from video port 1.
+          For AM625 DSS, the internal DPI output port node from video
+          port 1.
 
       port@1:
         $ref: /schemas/graph.yaml#/properties/port