i810 audio fixes 1/2

[Roderick Colenbrander]

Hi,

This is the first of two patches that will fix some problems on soundcards 
using the i810 audio codec. The main probem with this soundcard is that it 
only supports a frequency of 48kHz in 16bit stereo mode.

This first patch to dsound queries if the card supports 16bit and if so it 
uses it, else it uses 8bit. Further it also detects if the card supports 
stereo or not. The patch was inspired by one from transgaming to rewind but 
that patch did a bit the opposite (defaulting to 8bit ..).

Roderick Colenbrander