ramips: clean and improve MAC address setup in 02_network

This patch removes unnecessary MAC address setup statements in
ramips' 02_network by doing several optimizations:

1. For the following devices, lan_mac was set up with
   mtd_get_mac_binary although the same address was set in DTS.
   The lan_mac statement is removed in 02_network, but
   wan_mac is kept:
   - mercury,mac1200r-v2
   - phicomm,k2g
   - skylab,skw92a
   - wiznet,wizfi630a

2. For the following devices, wan_mac was set up with
   mtd_get_mac_binary although the same address was set in DTS.
   The wan_mac statement is removed in 02_network, no
   lan_mac is present:
   - buffalo,whr-g300n
   - glinet,gl-mt300n-v2
   - zyxel,keenetic-start

3. For the following device, lan_mac and wan_mac were set up
   with mtd_get_mac_binary to the same address as set in DTS.
   Both statements are removed in 02_network:
   - buffalo,whr-600d

4. For some devices, it was possible to move setup from 02_network
   to DTS by introducing previously missing mtd_mac_address:
   - buffalo,whr-1166d
   - buffalo,whr-300hp2
   - buffalo,wsr-600dhp
   - ohyeah,oy-0001
   - planex,vr500

5. For one device, mtd_mac_address was just wrong and overwritten
   by 02_network. Put the correct value in DTS and remove redundant
   statement in 02_network:
   - asus,rt-ac57u

6. For one device, MAC address defined in DTS is exchanged together
   with lan_mac/wan_mac setup in 02_network, so that cases in
   02_network can be merged:
   - phicomm,k2p

For some devices, an empty case has to be used to prevent them
from falling into the default case and have
WAN address = eth0 address + 1 set to them.

Signed-off-by: Adrian Schmutzler <freifunk@adrianschmutzler.de>

target/linux/ramips/dts/mt7620a_buffalo_whr-1166d.dts

@@ -144,6 +144,8 @@
 	pinctrl-names = "default";
 	pinctrl-0 = <&rgmii1_pins &mdio_pins>;
 
+	mtd-mac-address = <&factory 0x4>;
+
 	port@5 {
 		status = "okay";
 		phy-handle = <&phy5>;

target/linux/ramips/dts/mt7620a_buffalo_whr-300hp2.dts

@@ -143,6 +143,7 @@
 &ethernet {
 	pinctrl-names = "default";
 	pinctrl-0 = <&ephy_pins>;
+	mtd-mac-address = <&factory 0x4>;
 	mediatek,portmap = "llllw";
 };
 

target/linux/ramips/dts/mt7620a_ohyeah_oy-0001.dts

@@ -106,6 +106,7 @@
 &ethernet {
 	pinctrl-names = "default";
 	pinctrl-0 = <&ephy_pins>;
+	mtd-mac-address = <&factory 0x28>;
 	mediatek,portmap = "llllw";
 };
 

target/linux/ramips/dts/mt7621_asus_rt-ac57u.dts

@@ -135,7 +135,7 @@
 };
 
 &ethernet {
-	mtd-mac-address = <&factory 0x4e000>;
+	mtd-mac-address = <&factory 0xe000>;
 };
 
 &pinctrl {

target/linux/ramips/dts/mt7621_buffalo_wsr-600dhp.dts

@@ -181,6 +181,10 @@
 	};
 };
 
+&ethernet {
+	mtd-mac-address = <&factory 0x4>;
+};
+
 &xhci {
 	status = "disabled";
 };

target/linux/ramips/dts/mt7621_netgear_r6220.dtsi

@@ -107,7 +107,7 @@
 };
 
 &ethernet {
-	mtd-mac-address = <&factory 0x00000004>;
+	mtd-mac-address = <&factory 0x4>;
 };
 
 &pinctrl {

target/linux/ramips/dts/mt7621_phicomm_k2p.dts

@@ -109,7 +109,7 @@
 };
 
 &ethernet {
-	mtd-mac-address = <&factory 0xe006>;
+	mtd-mac-address = <&factory 0xe000>;
 };
 
 &pinctrl {

target/linux/ramips/dts/mt7621_planex_vr500.dts

@@ -81,6 +81,10 @@
 	};
 };
 
+&ethernet {
+	mtd-mac-address = <&factory 0xe000>;
+};
+
 &pinctrl {
 	state_default: pinctrl0 {
 		gpio {