hda_intel suspend latency: shorten codec read

not sleeping for every codec read/write but doing a short udelay and
a conditional reschedule has cut suspend+resume latency by about 1
second on my T60.

The patch also fixes the unexpected codec-connection errors that
happen more often in the new power-save mode:
    http://lkml.org/lkml/2007/11/8/255
    http://bugzilla.kernel.org/show_bug.cgi?id=9332



Signed-off-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>