Fix lack of BWM stats for WAN when using PPPoE
Increase MAX_SPEED_IF to 32. This define controls the number of
interfaces to parse from /proc/net/dev, as well as how many to load from
an rstats file on restoration, and how large the speed[] array should
be.
Depending on several factors (number of VLANs configured, use of OpenVPN
server and/or client, etc.), the ppp0 interface might not be within the
first 10 interfaces in /proc/net/dev.
Thanks to Rangaistus to tracking this down.
Reference: http://www.linksysinfo.org/index.php?threads/tomato-shibbys-releases.33858/page-75#post-284120