base-files: fix uci led oneshot/timer trigger

This patch adds a missing type property. This fixes
the creation of oneshot and timer led triggers like:

| ucidef_set_led_timer "system" "system" "zhuotk:green:system" "1000" "1000"

from /etc/init.d/01_leds.

Fixes: b06a286a48 ("base-files: cleanup led functions in uci-defaults.sh")
Signed-off-by: Robinson Wu <wurobinson@qq.com>
Signed-off-by: Christian Lamparter <chunkeey@gmail.com>

package/base-files/files/lib/functions/uci-defaults.sh

@@ -476,6 +476,7 @@ _ucidef_set_led_timer() {
 
 	_ucidef_set_led_common "$1" "$2" "$3"
 
+	json_add_string type "$trigger_name"
 	json_add_string trigger "$trigger_name"
 	json_add_int delayon "$delayon"
 	json_add_int delayoff "$delayoff"