Fix Bugg: Low wifi performance when adding new SSID on Pure

- Add the extra wifi interfaces into PPA via hotplug script, later after
they are created by hostapd.

- Note: Adding the extra wifi interfaces (when they don't exist) into PPA via
/etc/init.d/ppa may crash network system. For example, ifconfig is blocked by
some ioctl commands.

lq-wave-300_5_x/files/etc/hotplug.d/net/00-wifi-detect

 #!/bin/sh
 
-[ "${ACTION}" = "add" ] && [ "${INTERFACE%%[0-9]}" = "wlan" ] && {
-	/sbin/wifi config
+wlan_ppa_add() {
+	net=$1
+	ifn=$2
+
+	ppacmd "get${net}" |grep acc_rx |awk '{print$3}' |grep -wq "^$ifn$" || {
+		ppacmd "add${net}" -i "$ifn"
+	}
+}
+
+wlan_ppa_remove() {
+	net=$1
+	ifn=$2
+
+	ppacmd "get${net}" |grep acc_rx |awk '{print$3}' |grep -wq "^$ifn$" && {
+		ppacmd "del${net}" -i "$ifn"
+	}
 }
+
+wlan_ppa_process() {
+	cfg=$1
+
+	config_get ifname $cfg ifname
+
+	[ "$ifname" != "${INTERFACE}" ] && return
+
+	config_get network $cfg network
+
+	wlan_ppa_${ACTION} $network $ifname
+}
+
+[ "${INTERFACE%%[0-9.]*}" != "wlan" ] && return
+
+[ "${ACTION}" = "add" ] || [ "${ACTION}" = "remove" ] && {
+	config_load wireless
+
+	config_foreach wlan_ppa_process wifi-iface
+}
+
+[ "${ACTION}" = "add" ] && /sbin/wifi config