ramips: fix switch port order for TP-Link Archer C20i

Physical port order watched from the backside of the C20i
(from left to right) is: Internet / 1 / 2 / 3 / 4

Physical Port	Switch port
WAN             0
LAN 3           1
LAN 4           2
LAN 1           3
LAN 2           4
(not used)      5
CPU             6

Signed-off-by: Walter Sonius <[email protected]>
[commit message/title improvements]
Signed-off-by: Adrian Schmutzler <[email protected]>

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

@@ -67,7 +67,6 @@ ramips_setup_interfaces()
 	glinet,gl-mt300n|\
 	glinet,gl-mt750|\
 	hiwifi,hc5661|\
-	tplink,archer-c20i|\
 	wrtnode,wrtnode|\
 	zbtlink,zbt-wa05)
 		ucidef_add_switch "switch0" \
@@ -177,6 +176,7 @@ ramips_setup_interfaces()
 		ucidef_add_switch "switch0" \
 			"0:lan:3" "1:lan:2" "2:lan:1" "3:wan" "6@eth0"
 		;;
+	tplink,archer-c20i|\
 	tplink,archer-c20-v1|\
 	tplink,archer-c50-v1)
 		ucidef_add_switch "switch0" \