[dev][max98927] adjust the gain to 0dB

Change-Id: I5bd4348a99c663a8b7a003582034871cd4aa228c
diff --git a/system/dev/codec/max98927/max98927.cpp b/system/dev/codec/max98927/max98927.cpp
index 3f4880d..cfb258c 100644
--- a/system/dev/codec/max98927/max98927.cpp
+++ b/system/dev/codec/max98927/max98927.cpp
@@ -219,8 +219,8 @@
     // Default monomix input channel 1 is PCM RX channel 1
     WriteReg(PCM_SPK_MONOMIX_B, PCM_SPK_MONOMIX_B_CFG_CH1_SRC(1));
 
-    // Default volume (-13dB)
-    WriteReg(AMP_VOL_CTRL, 0x00);
+    // Default volume (0dB)
+    WriteReg(AMP_VOL_CTRL, 0x34);
     WriteReg(SPK_GAIN, SPK_GAIN_PCM(SPK_GAIN_3DB));
 
     // Enable DC blocking filter