gemini: Make a per-board case for ethernet MAC

The DNS-313 isn't the only special board so let's bite the
bullet and create a case ladder in preparation for DIR-685.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Christian Lamparter <chunkeey@gmail.com> [refreshed]
(cherry picked from commit 38d85d2c9fd9a3fd061fb56823821834dd720516)

target/linux/gemini/base-files/lib/preinit/05_set_ether_mac_gemini

@@ -9,17 +9,8 @@ set_ether_mac() {
 	local MAC1
 	local MAC2
 
-	# Most devices have a standard "VCTL" partition
-	part="$(find_mtd_part VCTL)"
-	if [ -n "$part" ]; then
-		MAC1="$(strings $part |grep MAC|cut -d: -f2|cut -c3-14|sed -e 's,\(..\),:\1,g' -e 's,^:,,')"
-		MAC2="$(strings $part |grep MAC|cut -d: -f8|cut -c3-14|sed -e 's,\(..\),:\1,g' -e 's,^:,,')"
-
-		ip link set eth0 address "$MAC1" 2>/dev/null
-		ip link set eth1 address "$MAC2" 2>/dev/null
-		return 0
-	fi
-
+	case "$(board_name)" in
+	dlink,dns-313)
 		# The DNS-313 has a special field in its RedBoot
 		# binary that we need to check
 		part="$(find_mtd_part RedBoot)"
@@ -31,6 +22,19 @@ set_ether_mac() {
 				return 0
 			fi
 		fi
+		;;
+	esac
+
+	# Most devices have a standard "VCTL" partition
+	part="$(find_mtd_part VCTL)"
+	if [ -n "$part" ]; then
+		MAC1="$(strings $part |grep MAC|cut -d: -f2|cut -c3-14|sed -e 's,\(..\),:\1,g' -e 's,^:,,')"
+		MAC2="$(strings $part |grep MAC|cut -d: -f8|cut -c3-14|sed -e 's,\(..\),:\1,g' -e 's,^:,,')"
+
+		ip link set eth0 address "$MAC1" 2>/dev/null
+		ip link set eth1 address "$MAC2" 2>/dev/null
+		return 0
+	fi
 }
 
 boot_hook_add preinit_main set_ether_mac