dt-bindings: mailbox: Correct example indentation

DTS example in the bindings should be indented with 2- or 4-spaces, so
correct a mixture of different styles to keep consistent 4-spaces.

Signed-off-by: Krzysztof Kozlowski <[e-mail]>
Reviewed-by: Nishanth Menon <[e-mail]>
Reviewed-by: Sven Peter <[e-mail]>
Acked-by: Rob Herring (Arm) <[e-mail]>
Signed-off-by: Jassi Brar <[e-mail]>

Documentation/devicetree/bindings/mailbox/allwinner,sun6i-a31-msgbox.yaml

···
     #include <dt-bindings/reset/sun8i-h3-ccu.h>
 
     msgbox: mailbox@1c17000 {
-            compatible = "allwinner,sun8i-h3-msgbox",
-                         "allwinner,sun6i-a31-msgbox";
-            reg = <0x01c17000 0x1000>;
-            clocks = <&ccu CLK_BUS_MSGBOX>;
-            resets = <&ccu RST_BUS_MSGBOX>;
-            interrupts = <GIC_SPI 49 IRQ_TYPE_LEVEL_HIGH>;
-            #mbox-cells = <1>;
+        compatible = "allwinner,sun8i-h3-msgbox",
+                     "allwinner,sun6i-a31-msgbox";
+        reg = <0x01c17000 0x1000>;
+        clocks = <&ccu CLK_BUS_MSGBOX>;
+        resets = <&ccu RST_BUS_MSGBOX>;
+        interrupts = <GIC_SPI 49 IRQ_TYPE_LEVEL_HIGH>;
+        #mbox-cells = <1>;
     };
 
 ...

Documentation/devicetree/bindings/mailbox/amlogic,meson-gxbb-mhu.yaml

···
 examples:
   - |
     mailbox@c883c404 {
-          compatible = "amlogic,meson-gxbb-mhu";
-          reg = <0xc883c404 0x4c>;
-          interrupts = <208>, <209>, <210>;
-          #mbox-cells = <1>;
+        compatible = "amlogic,meson-gxbb-mhu";
+        reg = <0xc883c404 0x4c>;
+        interrupts = <208>, <209>, <210>;
+        #mbox-cells = <1>;
     };

Documentation/devicetree/bindings/mailbox/apple,mailbox.yaml

···
 
 examples:
   - |
-        mailbox@77408000 {
-                compatible = "apple,t8103-asc-mailbox", "apple,asc-mailbox-v4";
-                reg = <0x77408000 0x4000>;
-                interrupts = <1 583 4>, <1 584 4>, <1 585 4>, <1 586 4>;
-                interrupt-names = "send-empty", "send-not-empty",
-                 "recv-empty", "recv-not-empty";
-                #mbox-cells = <0>;
-        };
+    mailbox@77408000 {
+        compatible = "apple,t8103-asc-mailbox", "apple,asc-mailbox-v4";
+        reg = <0x77408000 0x4000>;
+        interrupts = <1 583 4>, <1 584 4>, <1 585 4>, <1 586 4>;
+        interrupt-names = "send-empty", "send-not-empty",
+                          "recv-empty", "recv-not-empty";
+        #mbox-cells = <0>;
+    };

Documentation/devicetree/bindings/mailbox/ti,secure-proxy.yaml

···
   - |
     #include <dt-bindings/interrupt-controller/arm-gic.h>
     secure_proxy: mailbox@32c00000 {
-          compatible = "ti,am654-secure-proxy";
-          #mbox-cells = <1>;
-          reg-names = "target_data", "rt", "scfg";
-          reg = <0x32c00000 0x100000>,
-                <0x32400000 0x100000>,
-                <0x32800000 0x100000>;
-          interrupt-names = "rx_011";
-          interrupts = <GIC_SPI 32 IRQ_TYPE_LEVEL_HIGH>;
+        compatible = "ti,am654-secure-proxy";
+        #mbox-cells = <1>;
+        reg-names = "target_data", "rt", "scfg";
+        reg = <0x32c00000 0x100000>,
+              <0x32400000 0x100000>,
+              <0x32800000 0x100000>;
+        interrupt-names = "rx_011";
+        interrupts = <GIC_SPI 32 IRQ_TYPE_LEVEL_HIGH>;
     };