audio ioctl patch

[Mattias Engdegård]

I've posted a patch for audio (OSS) ioctl decoding. It has proven to be quite
useful for audio debugging. Please merge it if you have no objections.

I found no prevailing method how input-output parameters are displayed,
and the OSS api has plenty of them. I adopted the convention

ioctl(7, MY_IOCTL, {a=17, b=19} -> {a=47, b=11}) = 0

which seemed to be intuitive enough. I kept the "->" notation for some
output-only parameters as well to make the direction clear.

[I don't know if the maintainers are automatically notified when a new patch
is submitted. If so, I apologise for this superfluous message.]