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

@@ -9,6 +9,22 @@ set_ether_mac() {
 	local MAC1
 	local MAC2
 
+	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)"
+		if [ -n "$part" ]; then
+			DEVID="$(dd if=$part bs=1 skip=119508 count=7 2>/dev/null)"
+			if [ "$DEVID" = "dns-313" ]; then
+				MAC1="$(mtd_get_mac_binary RedBoot 119540)"
+				ip link set eth0 address "$MAC1" 2>/dev/null
+				return 0
+			fi
+		fi
+		;;
+	esac
+
 	# Most devices have a standard "VCTL" partition
 	part="$(find_mtd_part VCTL)"
 	if [ -n "$part" ]; then
@@ -19,18 +35,6 @@ set_ether_mac() {
 		ip link set eth1 address "$MAC2" 2>/dev/null
 		return 0
 	fi
-
-	# The DNS-313 has a special field in its RedBoot
-	# binary that we need to check
-	part="$(find_mtd_part RedBoot)"
-	if [ -n "$part" ]; then
-		DEVID="$(dd if=$part bs=1 skip=119508 count=7 2>/dev/null)"
-		if [ "$DEVID" = "dns-313" ]; then
-			MAC1="$(mtd_get_mac_binary RedBoot 119540)"
-			ip link set eth0 address "$MAC1" 2>/dev/null
-			return 0
-		fi
-	fi
 }
 
 boot_hook_add preinit_main set_ether_mac