modemmanager: EAP112 LTE to reconnect automatically after reboot

1. Copy modemmanager to feeds/ucentral.
2. Add function to find the device sysfs path when protocol is "wwan".
3. Call ifup when modem is ready for connection.
4. Add trigger to restart modemmanager when network uci is updated.

Fixes: WIFI-14751
Signed-off-by: Sebastian Huang <sebastian_huang@accton.com>

feeds/ucentral/modemmanager/files/usr/sbin/ModemManager-wrapper

@@ -0,0 +1,33 @@
+#!/bin/sh
+
+trap_with_arg() {
+	func="$1" ; shift
+	for sig ; do
+		# shellcheck disable=SC2064
+		trap "$func $sig" "$sig"
+	done
+}
+
+func_trap() {
+	logger "ModemManager-wrapper[$$]" "Sending signal ${1}..."
+	kill "-${1}" "$CHILD" 2>/dev/null
+}
+
+main() {
+	. /usr/share/ModemManager/modemmanager.common
+
+	trap_with_arg func_trap INT TERM KILL
+
+	mkdir -p "${MODEMMANAGER_RUNDIR}"
+	chmod 0755 "${MODEMMANAGER_RUNDIR}"
+	mm_cleanup_interfaces
+
+	/usr/sbin/ModemManager "$@" 1>/dev/null 2>/dev/null &
+	CHILD="$!"
+
+	mm_report_events_from_cache
+
+	wait "$CHILD"
+}
+
+main "$@"