dt-bindings: arm: amlogic: fix x96-max/sei510 section in amlogic.yaml

Move amediatech,x96-max and seirobotics,sei510 to the S905D2 section and
update the S905D2 description to S905D2/X2/Y2.
Signed-off-by: Christian Hewitt <christianshewitt@gmail.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Kevin Hilman <khilman@baylibre.com>

Documentation/devicetree/bindings/arm/amlogic.yaml

@@ -91,13 +91,11 @@ properties:
       - description: Boards with the Amlogic Meson GXL S905X SoC
         items:
           - enum:
-              - amediatech,x96-max
               - amlogic,p212
               - hwacom,amazetv
               - khadas,vim
               - libretech,cc
               - nexbox,a95x
-              - seirobotics,sei510
           - const: amlogic,s905x
           - const: amlogic,meson-gxl
 
@@ -129,10 +127,12 @@ properties:
           - const: amlogic,a113d
           - const: amlogic,meson-axg
 
-      - description: Boards with the Amlogic Meson G12A S905D2 SoC
+      - description: Boards with the Amlogic Meson G12A S905D2/X2/Y2 SoC
         items:
           - enum:
+              - amediatech,x96-max
               - amlogic,u200
+              - seirobotics,sei510
           - const: amlogic,g12a
 
       - description: Boards with the Amlogic Meson G12B A311D SoC