ALSA: fireworks: Add skelton for Fireworks based devices

This commit adds a new driver for devices based on Fireworks. This driver
just creates/removes card instance according to callbacks.

Fireworks is a board module which Echo Audio produced. This module
consists of three chipsets:
 - Communication chipset for IEEE1394 PHY/Link and IEC 61883-1/6
 - DSP or/and FPGA for signal processing
 - Flash Memory to store firmwares

Current supported devices:
 - Mackie Onyx 400F/1200F
 - Echo AudioFire12/8(until 2009 July)
 - Echo AudioFire2/4/Pre8/8(since 2009 July)
 - Echo Fireworks 8/HDMI
 - Gibson Robot Interface pack/GoldTop

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