dt-bindings: mfd: ti,j721e-system-controller: Add compatible strings for other platforms

There are multiple J7 based platforms, and the j721e-system-controller
shouldn't be define in non-j721e devices device trees.

This is mainly for clarity; but also useful in case there are future
erratas that need to be fixed for a specific platform.
Signed-off-by: Matt Ranostay <mranostay@ti.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Lee Jones <lee@kernel.org>
Link: https://lore.kernel.org/r/20221024035405.366208-2-mranostay@ti.com

Documentation/devicetree/bindings/mfd/ti,j721e-system-controller.yaml

@@ -26,7 +26,9 @@ properties:
   compatible:
     items:
       - enum:
+          - ti,j7200-system-controller
           - ti,j721e-system-controller
+          - ti,j721s2-system-controller
       - const: syscon
       - const: simple-mfd