From: Patrice Mandin
Subject: Reworked audio drivers for Atari platform

These are reworked audio drivers for the Atari platform.

Previous drivers were missing some features:
- Test external clock plugged to DSP port on Atari Falcon 030.
- Ability to select internal or external clock.

So now, I generate a list of frequencies available, with the master clock
and predivisor to use. One big caveat to this: I do not have an external
clock, so I hope it works.

--HG--
extra : convert_revision : svn%3Ac70aab31-4412-0410-b14c-859654838e24/trunk%40962