apm821xx: remove wd, mybooklive-duo leftovers

The unification of the My Book Live Single and duo image in
commit 9b47aa93c7 ("apm821xx: unify My Book Live Single + Duo images")
made the wd,mybooklive-duo obsolete in most places and can
be removed.

Signed-off-by: Christian Lamparter <chunkeey@gmail.com>

target/linux/apm821xx/base-files/etc/board.d/01_leds

@@ -23,8 +23,7 @@ meraki,mx60)
 	ucidef_set_led_switch "lan4" "LAN4" "mx60:green:lan4" "switch0" "0x02"
 	;;
 
-wd,mybooklive|\
-wd,mybooklive-duo)
+wd,mybooklive)
 	ucidef_set_led_ide "sata" "SATA" "mbl:blue:power"
 	;;
 

target/linux/apm821xx/base-files/lib/preinit/79_move_config

@@ -6,8 +6,7 @@ move_config() {
 	. /lib/functions.sh
 
 	case "$(board_name)" in
-	wd,mybooklive|\
-	wd,mybooklive-duo)
+	wd,mybooklive)
 		if [ -b $BOOTPART ]; then
 			mkdir -p /boot
 			mount -t ext4 -o rw,noatime $BOOTPART /boot

target/linux/apm821xx/base-files/lib/upgrade/platform.sh

@@ -7,8 +7,7 @@ platform_check_image() {
 	local board=$(board_name)
 
 	case "$board" in
-	wd,mybooklive|\
-	wd,mybooklive-duo)
+	wd,mybooklive)
 		mbl_do_platform_check "$1"
 		return $?;
 		;;
@@ -22,8 +21,7 @@ platform_do_upgrade() {
 	local board=$(board_name)
 
 	case "$board" in
-	wd,mybooklive|\
-	wd,mybooklive-duo)
+	wd,mybooklive)
 		mbl_do_upgrade "$ARGV"
 		;;
 	meraki,mr24|\