bootanimation: Tweak parameters for pcm_open for playing boot sounds.

Set start_threshold and avail_min to 1/4th period size and stop_threshold to INT_MAX

Change-Id: I0a3aac18533709daa86a024cdd6a32086410723a

cmds/bootanimation/AudioPlayer.cpp

@@ -272,6 +272,9 @@ bool AudioPlayer::threadLoop()
     config.rate = chunkFmt->sample_rate;
     config.period_size = mPeriodSize;
     config.period_count = mPeriodCount;
+    config.start_threshold = mPeriodSize / 4;
+    config.stop_threshold = INT_MAX;
+    config.avail_min = config.start_threshold;
     if (chunkFmt->bits_per_sample != 16) {
         ALOGE("only 16 bit WAV files are supported");
         goto exit;