[ALSA] Remove PCM xfer_align sw params

The xfer_align sw_params parameter has never been used in a sane manner,
and no one understands what this does exactly.  The current
implementation looks also buggy because it allows write of shorter size
than xfer_align.  So, if you do partial writes, the write isn't actually
aligned at all.
Removing this parameter will make some pcm_lib_* code more readable
(and less buggy).

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>
diff --git a/include/sound/asound.h b/include/sound/asound.h
index ee753d7..069d912 100644
--- a/include/sound/asound.h
+++ b/include/sound/asound.h
@@ -363,7 +363,7 @@
 	unsigned int period_step;
 	unsigned int sleep_min;			/* min ticks to sleep */
 	snd_pcm_uframes_t avail_min;		/* min avail frames for wakeup */
-	snd_pcm_uframes_t xfer_align;		/* xfer size need to be a multiple */
+	snd_pcm_uframes_t xfer_align;		/* obsolete: xfer size need to be a multiple */
 	snd_pcm_uframes_t start_threshold;	/* min hw_avail frames for automatic start */
 	snd_pcm_uframes_t stop_threshold;	/* min avail frames for automatic stop */
 	snd_pcm_uframes_t silence_threshold;	/* min distance from noise for silence filling */