Fix kernelversion.h

Add missing pragma once and static inline all functions.

Bug: 202086915
Bug: 157552970
Test: builds
Change-Id: I8aca683e9e60c33bf5a5ac45cc20c2e59c8eecde
diff --git a/staticlibs/native/tcutils/tcutils.cpp b/staticlibs/native/tcutils/tcutils.cpp
index e30a500..00f3c56 100644
--- a/staticlibs/native/tcutils/tcutils.cpp
+++ b/staticlibs/native/tcutils/tcutils.cpp
@@ -34,6 +34,7 @@
 #include <linux/rtnetlink.h>
 #include <net/if.h>
 #include <stdarg.h>
+#include <stdio.h>
 #include <sys/socket.h>
 #include <unistd.h>
 #include <utility>