ramips/mt7621: mikrotik: don't use mtd-mac-address in DTS

As evidenced here[1] the device MAC address can be stored at a random
offset in the hard_config partition. Rely on sysfs to update the MAC
address correctly.

Adjust config so that WAN is base MAC and LAN is base MAC +1 to better
match label and vendor OS.

[1] https://github.com/openwrt/openwrt/pull/2850#issuecomment-610809021

Signed-off-by: Thibaut VARÈNE <hacks@slashdirt.org>

target/linux/ramips/dts/mt7621_mikrotik_routerboard-750gr3.dts

@@ -126,10 +126,6 @@
 	};
 };
 
-&gmac0 {
-	mtd-mac-address = <&hard_config 0x0010>;
-};
-
 &switch0 {
 	ports {
 		port@0 {
@@ -140,29 +136,21 @@
 		port@1 {
 			status = "okay";
 			label = "lan2";
-			mtd-mac-address = <&hard_config 0x0010>;
-			mtd-mac-address-increment = <1>;
 		};
 
 		port@2 {
 			status = "okay";
 			label = "lan3";
-			mtd-mac-address = <&hard_config 0x0010>;
-			mtd-mac-address-increment = <2>;
 		};
 
 		port@3 {
 			status = "okay";
 			label = "lan4";
-			mtd-mac-address = <&hard_config 0x0010>;
-			mtd-mac-address-increment = <3>;
 		};
 
 		port@4 {
 			status = "okay";
 			label = "lan5";
-			mtd-mac-address = <&hard_config 0x0010>;
-			mtd-mac-address-increment = <4>;
 		};
 	};
 };

target/linux/ramips/dts/mt7621_mikrotik_routerboard-m11g.dts

@@ -134,11 +134,6 @@
 	};
 };
 
-&gmac0 {
-	mtd-mac-address = <&hard_config 0x0010>;
-	mtd-mac-address-increment = <1>;
-};
-
 &switch0 {
 	ports {
 		port@0 {

target/linux/ramips/dts/mt7621_mikrotik_routerboard-m33g.dts

@@ -158,18 +158,11 @@
 	};
 };
 
-&gmac0 {
-	mtd-mac-address = <&hard_config 0x0010>;
-	mtd-mac-address-increment = <1>;
-};
-
 &switch0 {
 	ports {
 		port@0 {
 			status = "okay";
 			label = "wan";
-			mtd-mac-address = <&hard_config 0x0010>;
-			mtd-mac-address-increment = <2>;
 		};
 
 		port@1 {

target/linux/ramips/mt7621/base-files/etc/board.d/02_network

@@ -91,9 +91,12 @@ ramips_setup_macs()
 		wan_mac=$(mtd_get_mac_ascii u-boot-env wanaddr)
 		label_mac=$wan_mac
 		;;
+	mikrotik,routerboard-750gr3|\
 	mikrotik,routerboard-m11g|\
 	mikrotik,routerboard-m33g)
-		label_mac=$(mtd_get_mac_binary hard_config 0x10)
+		label_mac=$(cat "/sys/firmware/mikrotik/hard_config/mac_base")
+		wan_mac=$label_mac
+		lan_mac=$(macaddr_add $label_mac 1)
 		;;
 	zbtlink,zbt-we1326|\
 	zbtlink,zbt-wg3526-16m|\