treewide: remove label = "cpu" from DSA dt-binding

This is not used by the DSA dt-binding, so remove it from all devicetrees.

Link: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=9cc115d8d6f73dd260de1609182f3645844d6907
Signed-off-by: Arınç ÜNAL <arinc.unal@arinc9.com>

target/linux/bmips/dts/bcm6318.dtsi

@@ -400,7 +400,6 @@
 
 				port@8 {
 					reg = <8>;
-					label = "cpu";
 
 					phy-mode = "internal";
 					ethernet = <&ethernet>;

target/linux/bmips/dts/bcm63268.dtsi

@@ -521,7 +521,6 @@
 
 				port@8 {
 					reg = <8>;
-					label = "cpu";
 
 					phy-mode = "internal";
 					ethernet = <&ethernet>;

target/linux/bmips/dts/bcm6328.dtsi

@@ -418,7 +418,6 @@
 
 				port@8 {
 					reg = <8>;
-					label = "cpu";
 
 					phy-mode = "internal";
 					ethernet = <&ethernet>;

target/linux/bmips/dts/bcm6362.dtsi

@@ -515,7 +515,6 @@
 
 				port@8 {
 					reg = <8>;
-					label = "cpu";
 
 					phy-mode = "internal";
 					ethernet = <&ethernet>;

target/linux/bmips/dts/bcm6368.dtsi

@@ -529,7 +529,6 @@
 
 				port@8 {
 					reg = <8>;
-					label = "cpu";
 
 					phy-mode = "internal";
 					ethernet = <&ethernet>;