Update to kernel headers v4.12.3.

Test: NA
Change-Id: Iee3d607e8a0fe866ffa1f123308af0713719ea29
diff --git a/original/uapi/linux/un.h b/original/uapi/linux/un.h
index 3ed3e46..4f0ab3a 100644
--- a/original/uapi/linux/un.h
+++ b/original/uapi/linux/un.h
@@ -10,4 +10,6 @@
 	char sun_path[UNIX_PATH_MAX];	/* pathname */
 };
 
+#define SIOCUNIXFILE (SIOCPROTOPRIVATE + 0) /* open a socket file with O_PATH */
+
 #endif /* _LINUX_UN_H */