dt-bindings: interrupt-controller: arm,versatile-fpga-irq: mark oxnas compatible as deprecated

Due to lack of maintenance and stall of development for a few years now,
and since no new features will ever be added upstream, mark the
OX810 and OX820 IRQ compatible as deprecated.
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Daniel Golle <daniel@makrotopia.org>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20230814-topic-oxnas-upstream-remove-v3-2-e2ba579a49d3@linaro.orgSigned-off-by: Neil Armstrong <neil.armstrong@linaro.org>

Documentation/devicetree/bindings/interrupt-controller/arm,versatile-fpga-irq.txt

@@ -6,7 +6,7 @@ controllers are OR:ed together and fed to the CPU tile's IRQ input. Each
 instance can handle up to 32 interrupts.
 
 Required properties:
-- compatible: "arm,versatile-fpga-irq" or "oxsemi,ox810se-rps-irq"
+- compatible: "arm,versatile-fpga-irq"
 - interrupt-controller: Identifies the node as an interrupt controller
 - #interrupt-cells: The number of cells to define the interrupts.  Must be 1
   as the FPGA IRQ controller has no configuration options for interrupt
@@ -19,6 +19,8 @@ Required properties:
   the system till not make it possible for devices to request these
   interrupts.
 
+The "oxsemi,ox810se-rps-irq" compatible is deprecated.
+
 Example:
 
 pic: pic@14000000 {