Enable MAX98357 audio driver

Bug: 143917131
Test: aplay and gst-launch-1.0 to play wave files.

Change-Id: Ic4b3c4c5a07aa1a2944f1b93087885fee599aa40
diff --git a/debian/defconfig b/debian/defconfig
index 5d4069e..9702f62 100644
--- a/debian/defconfig
+++ b/debian/defconfig
@@ -16,6 +16,8 @@
 CONFIG_I2C_CHARDEV=y
 CONFIG_SND_SOC_FSL_ASOC_CARD=n
 CONFIG_SND_GOOGLE_EDGETPU_CARD=y
+CONFIG_SND_SOC_IMX_MAX98357A=y
+CONFIG_SND_SOC_MAX98357A=y
 CONFIG_SND_SOC_RT5645=y
 CONFIG_SND_SOC_RT5631=y
 CONFIG_SND_SOC_RL6231=y