bebob/fireworks: add get_info/lock/unlock mechanism via hwdep interface

This commit add hwdep interface. The main purpose is to get information
as firewire device, lock/unlock kernel streaming. These functions are good for
control panel/mixer application.

Usage:
1.get fw_card_info via ioctl(2) with SNDRV_FIREWIRE_IOCTL_GET_INFO
2.lock kernel streaming via ioctl(2) with SNDRV_FIREWIRE_IOCTL_LOCK
3.unlock kernel streaming via ioctl(2) with SNDRV_FIREWIRE_IOCTL_UNLOCK
4.When it's readable (use poll(2) or anything), read fw_card event.
  This event is different depending on the type of fw_card. In most case,
  this event is SNDRV_FIREWIRE_EVENT_LOCK_STATUS and the content of buffer
  is struct snd_firewire_event_lock_status.
add monitor as hwdep interface application