dt-bindings: bus: uniphier-system-bus: fix warning in example

Since commit e69f5dc6 ("dt-bindings: serial: Convert 8250 to
json-schema"), the schema for "ns16550a" is checked.

'make dt_binding_check' emits the following warning:

  uart@5,00200000: $nodename:0: 'uart@5,00200000' does not match '^serial(@[0-9a-f,]+)*$'

Rename the node to follow the pattern defined in
Documentation/devicetree/bindings/serial/serial.yaml

While I was here, I removed leading zeros from unit names.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Link: https://lore.kernel.org/r/20200623113242.779241-1-yamada.masahiro@socionext.comSigned-off-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/bus/socionext,uniphier-system-bus.yaml

@@ -80,14 +80,14 @@ examples:
         ranges = <1 0x00000000 0x42000000 0x02000000>,
                  <5 0x00000000 0x46000000 0x01000000>;
 
-        ethernet@1,01f00000 {
+        ethernet@1,1f00000 {
             compatible = "smsc,lan9115";
             reg = <1 0x01f00000 0x1000>;
             interrupts = <0 48 4>;
             phy-mode = "mii";
         };
 
-        uart@5,00200000 {
+        serial@5,200000 {
             compatible = "ns16550a";
             reg = <5 0x00200000 0x20>;
             interrupts = <0 49 4>;