fff-wireless: add workaround for wifi configuration after update

Introduce a workaround for an OpenWrt bug on the Xiaomi Mi 4A (Gigabit
Edition). After an update of the firmware, the wireless interfaces are
not properly created as configured.

When configuring the WiFi interfaces via uci and applying the
settings using reload_config, hostapd reports errors and no WiFi
interfaces are created.

It seems like OpenWrt tries to dynamically reload the settings instead
of restarting hostapd, but hostapd fails to properly apply them.

To work around this regression until the root cause is found, restart
the wifi interfaces manually after a firmware upgrade.

Fixes: #319

Signed-off-by: Fabian Bläse <fabian@blaese.de>

src/packages/fff/fff-wireless/files/etc/init.d/fff-wireless-update

@@ -0,0 +1,21 @@
+#!/bin/sh /etc/rc.common
+
+START=99
+
+boot() {
+	# first we disable the init.d
+	/etc/init.d/fff-wireless-update disable
+	# we must delete the symlink manually
+	rm -f /etc/rc.d/S99fff-wireless-update
+
+	# Starting with OpenWrt 23.05, reload_config does not
+	# properly start the wifi access point on some devices.
+	# This seems to be an issue with the reloading of hostapd,
+	# which throws errors, but does not restart hostapd.
+	# see https://git.freifunk-franken.de/freifunk-franken/firmware/issues/319
+	#
+	# workaround: manually restart wifi completely
+	# after any automatic post-update configuration (fff-layer3-config, ...)
+	sleep 20
+	wifi
+}