GTA02: fix for clicking noise and JACK_INSERT interrupts

[Werner Almesberger]

Andy Green wrote:
> We need to discuss with hardware / GSM people tomorrow to eradicate this
> crazy circuit on A6 by piping GSM data via USB or WLAN or anything else
> than this.

USB or WLAN may be tricky for some of the things that run through
that piece of weirdness, but I think just a fixture that connects
to the appropriate testpoints would do nicely. As far as I know,
the board is in a fixture at that point in time anyway.

For simple firmware upgrades, we should make FLUID running on the
Neo work again. (If it ever was broken.)

Considering all the problems that GSM download circuit is causing
these days, I'd agree that it has overstayed its welcome.

- Werner