Removed CONFIG_USB_CDC_COMPOSITE=y from defconfig.

This defines a separate USB-Ethernet gadget that prevents aiy-gadget
from starting properly.

Change-Id: I57a5480c8c84e46eddb801b9ffc63a5c87147333
diff --git a/defconfig b/defconfig
index 60c3e68..00b6791 100644
--- a/defconfig
+++ b/defconfig
@@ -77,5 +77,4 @@
 CONFIG_GOOGLE_APEX_POWER=y
 
 CONFIG_USB_G_HID=y
-CONFIG_USB_CDC_COMPOSITE=y