Revert "Merge branch 'mv88e6xxx-dsa-bindings'"

This reverts the following commits:

commit 53313ed ("dt-bindings: marvell: Add Marvell MV88E6060 DSA schema")
commit 0f35369 ("dt-bindings: marvell: Rewrite MV88E6xxx in schema")
commit 605a5f5 ("ARM64: dts: marvell: Fix some common switch mistakes")
commit bfedd84 ("ARM: dts: nxp: Fix some common switch mistakes")
commit 2b83557 ("ARM: dts: marvell: Fix some common switch mistakes")
commit ddae07c ("dt-bindings: net: mvusb: Fix up DSA example")
commit b5ef617 ("dt-bindings: net: dsa: Require ports or ethernet-ports")

As repoted by Vladimir, it breaks boot on the Turris MOX board.

Link: https://lore.kernel.org/all/20231025093632.fb2qdtunzaznd73z@skbuf/
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Documentation/devicetree/bindings/net/dsa/dsa.yaml

@@ -46,10 +46,4 @@ $defs:
             $ref: dsa-port.yaml#
             unevaluatedProperties: false
 
-oneOf:
-  - required:
-      - ports
-  - required:
-      - ethernet-ports
-
 ...