arm64: dts: uniphier: ld20-global: drop audio codec port unit address

Audio codec port does not have "reg", thus it should not have unit
address, as reported by dtc W=1 warning:

  uniphier-ld20-global.dts:127.10-132.5: Warning (unit_address_vs_reg): /soc@0/i2c@58780000/tas5707@1b/port@0: node has a unit name, but no reg or ranges property
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Link: https://lore.kernel.org/r/20240401140952.97923-4-krzk@kernel.org

arch/arm64/boot/dts/socionext/uniphier-ld20-global.dts

@@ -124,7 +124,7 @@ audio-codec@1b {
 		PVDD_C-supply = <&amp_vcc_reg>;
 		PVDD_D-supply = <&amp_vcc_reg>;
 
-		port@0 {
+		port {
 			tas_speaker: endpoint {
 				dai-format = "i2s";
 				remote-endpoint = <&i2s_hpcmout1>;