Missing support for RJ11 on Guitar

[dglaude]

There is an external button/pedal that you can plug with an RJ11 connector to the "bass".

Found this description and the bit for that "button":
"PB is the button triggered by a cancelled effects pedal via the RJ11 expansion port at the controller base."

From http://wiibrew.org/wiki/Wiimote/Extension_Controllers/Guitar_Hero_(Wii)_Guitars

It would be a nice to have (and very interesting for my port of guitar to drums. :-)