dt-bindings: timer: oxsemi,rps-timer: remove obsolete bindings

Due to lack of maintenance and stall of development for a few years now,
and since no new features will ever be added upstream, remove the
OX810 and OX820 timer bindings.
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Daniel Golle <daniel@makrotopia.org>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Acked-by: Andy Shevchenko <andy@kernel.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20230630-topic-oxnas-upstream-remove-v2-4-fb6ab3dea87c@linaro.org

Documentation/devicetree/bindings/timer/oxsemi,rps-timer.txt

-Oxford Semiconductor OXNAS SoCs Family RPS Timer
-================================================
-
-Required properties:
-- compatible: Should be "oxsemi,ox810se-rps-timer" or "oxsemi,ox820-rps-timer"
-- reg : Specifies base physical address and size of the registers.
-- interrupts : The interrupts of the two timers
-- clocks : The phandle of the timer clock source
-
-example:
-
-timer0: timer@200 {
-	compatible = "oxsemi,ox810se-rps-timer";
-	reg = <0x200 0x40>;
-	clocks = <&rpsclk>;
-	interrupts = <4 5>;
-};