[ALSA] Fix capture on OSS emulation

ALSA<-OSS emulation
Fix the noisy capture on some hardwares over OSS emulation.
Change back to avail_min = period_size for capture direction.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/core/oss/pcm_oss.c

@@ -464,7 +464,8 @@ static int snd_pcm_oss_change_params(snd_pcm_substream_t *substream)
 	sw_params->tstamp_mode = SNDRV_PCM_TSTAMP_NONE;
 	sw_params->period_step = 1;
 	sw_params->sleep_min = 0;
-	sw_params->avail_min = 1;
+	sw_params->avail_min = substream->stream == SNDRV_PCM_STREAM_PLAYBACK ?
+		1 : runtime->period_size;
 	sw_params->xfer_align = 1;
 	if (atomic_read(&runtime->mmap_count) ||
 	    (substream->oss.setup && substream->oss.setup->nosilence)) {