dt-bindings: iio: adc: imx93: drop the 4th interrupt

Per i.MX93 Reference Mannual Rev.4, 12/2013, there is no interrupt 268,
so drop it.
Signed-off-by: Peng Fan <peng.fan@nxp.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20240226130826.3824251-1-peng.fan@oss.nxp.comSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Documentation/devicetree/bindings/iio/adc/nxp,imx93-adc.yaml

@@ -31,7 +31,6 @@ properties:
       - description: normal conversion, include EOC (End of Conversion),
           ECH (End of Chain), JEOC (End of Injected Conversion) and
           JECH (End of injected Chain).
-      - description: Self-testing Interrupts.
 
   clocks:
     maxItems: 1
@@ -70,8 +69,7 @@ examples:
             reg = <0x44530000 0x10000>;
             interrupts = <GIC_SPI 217 IRQ_TYPE_LEVEL_HIGH>,
                          <GIC_SPI 218 IRQ_TYPE_LEVEL_HIGH>,
-                         <GIC_SPI 219 IRQ_TYPE_LEVEL_HIGH>,
-                         <GIC_SPI 268 IRQ_TYPE_LEVEL_HIGH>;
+                         <GIC_SPI 219 IRQ_TYPE_LEVEL_HIGH>;
             clocks = <&clk IMX93_CLK_ADC1_GATE>;
             clock-names = "ipg";
             vref-supply = <&reg_vref_1v8>;