[RFT]: RME HDSPe AIO sound driver

[Ruslan Bukin]

Hi!

This is driver for RME HDSPe AIO (PCIe - series),
professional-grade ($800) sound card.

Many things not implemented (like MIDI in/out, 
TCO, WCM and other expansion boards).

So only analog and digital in/out are available.

Driver registers 8 out and 7 in stereo channels,
each represented as separate device, ie:
/dev/dsp%d.p%d
/dev/dsp%d.r%d

Card frequency is in range (32..192) KHz
and period size (32..4096) samples.

Period size is exported to dev.pcm.%d.period
sysctl.

Tested on latest HEAD only.

patch here:
http://bsdpad.com/hdspe/

-Ruslan