Fix surroundX PCM

Fix surroundX PCM
From: Julian Scheel <julian@jusst.de>

Hi all,

attached is an updated ICE1724.conf - I have added channels X parameters to
the .pcm.surroundXX-fields, because otherwise it's for example not possible
to play a 5.1-stream on surround51 and a stereo-stream on side simultaneous.
I need this feature to do multiroom-sound through one single sound-card (one
room playing a DVD with 5.1, another room playing some MP3s through channels
7 and 8).
I hope you could follow my explanations and will add this to the tree.

Cheers,
Julian