staging: bcm2835-audio: Add 10ms period constraint

It seems that the resolution of vc04 callback is in 10 msec; i.e. the
minimal period size is also 10 msec.

This patch adds the corresponding hw constraint.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Tested-by: Stefan Wahren <stefan.wahren@i2se.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/vc04_services/bcm2835-audio/bcm2835-pcm.c

@@ -145,6 +145,11 @@ static int snd_bcm2835_playback_open_generic(
 				   SNDRV_PCM_HW_PARAM_PERIOD_BYTES,
 				   16);
 
+	/* position update is in 10ms order */
+	snd_pcm_hw_constraint_minmax(runtime,
+				     SNDRV_PCM_HW_PARAM_PERIOD_TIME,
+				     10 * 1000, UINT_MAX);
+
 	chip->alsa_stream[idx] = alsa_stream;
 
 	chip->opened |= (1 << idx);