maestro3 mpsafe patch

[Pyun YongHyeon]

Here is patch for mpsafe maestro3(4). 
There is one known LOR in module unload. But the LOR complaint
message is misleading since it's not legal to grab sx lock while
holding mutex. I think the fix would be hard without cleaning up
many parts of audio subsystem. But the complaint would be harmless
if sndstat is not accessed during module unload.

The patch was tested on an old notebook. Becasue the notebook is UP
machine I had no chance to run the patch on real SMP hardware. :(
The patch is available at:
http://people.freebsd.org/~yongari/maestro3.mpsafe.patch.0509

Feedbacks are welcome.
-- 
Regards,
Pyun YongHyeon
http://www.kr.freebsd.org/~yongari	|	yongari at freebsd.org