dt-bindings: mailbox: remove the IPCC "wakeup" IRQ

The stm32 ipcc mailbox driver supports only two interrupts (rx and tx), so
remove the unsupported "wakeup" one.

Signed-off-by: Fabien Dessenne <[e-mail]>
Reviewed-by: Rob Herring <[e-mail]>
Signed-off-by: Jassi Brar <[e-mail]>

Documentation/devicetree/bindings/mailbox/st,stm32-ipcc.yaml

···
     items:
       - description: rx channel occupied
       - description: tx channel free
-      - description: wakeup source
-    minItems: 2
 
   interrupt-names:
     items:
       - const: rx
       - const: tx
-      - const: wakeup
-    minItems: 2
 
   wakeup-source: true
 
···
       #mbox-cells = <1>;
       reg = <0x4c001000 0x400>;
       st,proc-id = <0>;
-      interrupts-extended = <&intc GIC_SPI 100 IRQ_TYPE_NONE>,
-      		      <&intc GIC_SPI 101 IRQ_TYPE_NONE>,
-      		      <&aiec 62 1>;
-      interrupt-names = "rx", "tx", "wakeup";
+      interrupts-extended = <&exti 61 1>,
+                            <&intc GIC_SPI 101 IRQ_TYPE_LEVEL_HIGH>;
+      interrupt-names = "rx", "tx";
       clocks = <&rcc_clk IPCC>;
       wakeup-source;
     };