ramips: remove duplicate case for MAC setup of freestation5

ARC FreeStation5 is present twice in MAC address setup.

From older commits/changes, it is not possible to reconstruct
the correct choice only by reading the annotations.

Thus, remove the second case and keep the first one, so behavior
stays the same (as nobody seems to have complained about it).

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

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

@@ -519,7 +519,6 @@ ramips_setup_macs()
 	skylab,skw92a)
 		wan_mac=$(mtd_get_mac_binary factory 0x2e)
 		;;
-	arcwireless,freestation5|\
 	dlink,dir-300-b7|\
 	dlink,dir-320-b1|\
 	dlink,dir-620-a1|\