Fix panic caused by full duplex operation.
Fix panic caused by full duplex operation.

From the PR:
---snip---
The vibra16X supports full duplex. I traced the Windows driver, and what is
does is that it programs one DMA channel 8-bit, and the other 16-bit. There
might be some kind of auto detection logic here, because it always uses 8-bit
for playback, even if I play 16-bit sound ...
---snip---

PR:		80977
Submitted by:	Hans Petter Selasky <hselasky@c2i.net>

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