ramips: fix MAC address assignment for ASUS RT-AC51U

The current MAC address assignment for the ASUS RT-AC51U is "wrong",
it actually should be the same as for the RT-AC54U. Fix it.

MAC assignment based on vendor firmware:

  2g    0x4	label
  5g    0x8004	label +4
  lan   0x22	label +4
  wan   0x28	label

Thanks to Davide Fioravanti for checking this on his device.

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

target/linux/ramips/dts/mt7620a_asus_rt-ac51u.dts

@@ -36,7 +36,7 @@
 };
 
 &ethernet {
-	mtd-mac-address = <&factory 0x4>;
+	mtd-mac-address = <&factory 0x22>;
 };
 
 &state_default {

target/linux/ramips/mt7620/base-files/etc/board.d/02_network

@@ -236,7 +236,6 @@ ramips_setup_macs()
 
 	case $board in
 	aigale,ai-br100|\
-	asus,rt-ac51u|\
 	asus,rt-n12p|\
 	asus,rt-n14u|\
 	bdcom,wap2100-sk|\
@@ -272,6 +271,7 @@ ramips_setup_macs()
 		wan_mac=$(mtd_get_mac_binary factory 0x2e)
 		label_mac=$(mtd_get_mac_binary factory 0x4)
 		;;
+	asus,rt-ac51u|\
 	asus,rt-ac54u)
 		wan_mac=$(mtd_get_mac_binary factory 0x28)
 		label_mac=$wan_mac