i2s: Adjust fifo buffer size to match real hardware

Change-Id: I4caf9aaa45f9be0b254f446fa51705b7f54083ff

shodan_infrastructure/MatchaI2S.cs

diff --git a/shodan_infrastructure/MatchaI2S.cs b/shodan_infrastructure/MatchaI2S.cs
index 0591490..be3a3da 100644
--- a/shodan_infrastructure/MatchaI2S.cs
+++ b/shodan_infrastructure/MatchaI2S.cs
@@ -108,7 +108,7 @@
 
         public uint Count { get { lock(synclock) { return count; } } }
 
-        const uint FIFO_SIZE = 64;
+        const uint FIFO_SIZE = 32;
         const uint FIFO_MASK = FIFO_SIZE - 1;
 
         private uint cursor_r = 0;