kernel: drop empty kmod-ledtrig-* packages

The following four led triggers are enabled in generic config.

* kmod-ledtrig-default-on
* kmod-ledtrig-heartbeat
* kmod-ledtrig-netdev
* kmod-ledtrig-timer

Drop the packages and remove them from DEVICE_PACKAGES.
There's no other package depending on them in this repo.

Signed-off-by: Sungbo Eo <mans0n@gorani.run>

target/linux/mxs/profiles/01-duckbill.mk

@@ -10,7 +10,7 @@ define Profile/duckbill
   FEATURES+=usbgadget
   PACKAGES+= \
 	-dnsmasq -firewall -ppp -ip6tables -iptables -6relayd -mtd uboot-envtools \
-	kmod-leds-gpio kmod-ledtrig-timer -kmod-ipt-nathelper uboot-mxs-duckbill
+	kmod-leds-gpio -kmod-ipt-nathelper uboot-mxs-duckbill
 endef
 
 define Profile/duckbill/Description

target/linux/mxs/profiles/02-olinuxino-maxi.mk

@@ -9,7 +9,7 @@ define Profile/olinuxino-maxi
   NAME:=Olimex OLinuXino Maxi/Mini boards
   PACKAGES += imx-bootlets uboot-mxs-mx23_olinuxino \
 	  kmod-usb-net-smsc95xx kmod-gpio-mcp23s08 \
-	  kmod-leds-gpio kmod-ledtrig-heartbeat kmod-sound-core
+	  kmod-leds-gpio kmod-sound-core
 endef
 
 define Profile/olinuxino-maxi/Description

target/linux/mxs/profiles/03-olinuxino-micro.mk

@@ -8,7 +8,7 @@
 define Profile/olinuxino-micro
   NAME:=Olimex OLinuXino Micro/Nano boards
   PACKAGES += imx-bootlets uboot-mxs-mx23_olinuxino \
-	  kmod-gpio-mcp23s08 kmod-leds-gpio kmod-ledtrig-heartbeat
+	  kmod-gpio-mcp23s08 kmod-leds-gpio
 endef
 
 define Profile/olinuxino-micro/Description