[ALSA] Several fixes for the Sun DBRI driver

SPARC DBRI driver
This patch contains the following fixes to the Alsa DBRI driver:

- Remove 2.6.13 build warning on the prom_getproperty() call.

- Rework command synchronization: send a sequence number with D_WAIT,
  and check it in the completion interrupt.
  Move synchronization delays from _cmdsend() to _cmdlock() allowing the
  CPU to do other usefull things while the DBRI is processing the
  commands.

- Fix first argument of printk() calls.

- Enable burst transfers for DBRI. Original 2.4 patch from Krzysztof
  Helt

- Make dbri_debug module parameter writable from sysfs. Remove obsolete
  write access to the /proc debug file.

- Replace udelay() with msleep_interruptible() where possible.

- Update documentation comments.

Signed-off-by: Martin Habets <errandir_news@mph.eclipse.co.uk>
Signed-off-by: Takashi Iwai <tiwai@suse.de>