Updated to v4.4.1 kernel headers.

Bug: 23789423
Change-Id: I45ef68b3955c1f4d91ed53db8c519fce64d57f09
diff --git a/original/uapi/linux/usb/functionfs.h b/original/uapi/linux/usb/functionfs.h
index 295ba29..108dd79 100644
--- a/original/uapi/linux/usb/functionfs.h
+++ b/original/uapi/linux/usb/functionfs.h
@@ -20,6 +20,7 @@
 	FUNCTIONFS_HAS_SS_DESC = 4,
 	FUNCTIONFS_HAS_MS_OS_DESC = 8,
 	FUNCTIONFS_VIRTUAL_ADDR = 16,
+	FUNCTIONFS_EVENTFD = 32,
 };
 
 /* Descriptor of an non-audio endpoint */