DT schema expects node names to match certain.  This fixes dtbs_check
warnings like:
  sparx5_pcb134_emmc.dtb: i2c0-emux@0: $nodename:0: 'i2c0-emux@0' does not match '^(i2c-?)?mux'
and dtc W=1 warnings:
  sparx5_pcb134_board.dtsi:398.25-403.4: Warning (unique_unit_address_if_enabled): /axi@
600000000/i2c0-imux@0: duplicate unit-address (also used in node /axi@
600000000/i2c0-emux@0)
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Reviewed-by: Steen Hegelund <Steen.Hegelund@microchip.com>
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
 };
 
 &axi {
-       i2c0_imux: i2c0-imux@0 {
+       i2c0_imux: i2c-mux-0 {
                compatible = "i2c-mux-pinctrl";
                #address-cells = <1>;
                #size-cells = <0>;
                i2c-parent = <&i2c0>;
        };
-       i2c0_emux: i2c0-emux@0 {
+       i2c0_emux: i2c-mux-1 {
                compatible = "i2c-mux-gpio";
                #address-cells = <1>;
                #size-cells = <0>;