ALSA: fireface: add support for Fireface 800 with MIDI functionality only

Fireface 800 is a flagship model of RME GmbH for audio and music units
on IEEE 1394 bus, shipped 2004. This model consists of four chips:
 - TI TSB81BA3D for physical layer on cable environment of EEE 1394 bus
 - TI TSB82AA2 for link layer for 1394 OHCI bus bridge to PCI bus
 - Xilinx Spartan-3 FPGA XC3S400
 - Xilinx High-Performance CPLD XC9572XL

This commit adds support Fireface 800. In this time, the support is
restricted to its MIDI functionality, thus this commit adds some
condition statements to avoid touching streaming functionality.

Unlike Fireface 400, Fireface 800 has no functionality to suppress
asynchronous transactions for MIDI messages except for unregister of
listen address in controller side, thus the feature is available as is.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>