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/kernelversion.h b/staticlibs/native/tcutils/kernelversion.h
index 59b9e05..3be1ad2 100644
--- a/staticlibs/native/tcutils/kernelversion.h
+++ b/staticlibs/native/tcutils/kernelversion.h
@@ -23,6 +23,8 @@
 // In the mean time copying verbatim from:
 //   frameworks/libs/net/common/native/bpf_headers
 
+#pragma once
+
 #include <stdio.h>
 #include <sys/utsname.h>
 
@@ -30,7 +32,7 @@
 
 namespace android {
 
-unsigned kernelVersion() {
+static inline unsigned kernelVersion() {
   struct utsname buf;
   int ret = uname(&buf);
   if (ret)
@@ -49,8 +51,9 @@
   return KVER(kver_major, kver_minor, kver_sub);
 }
 
-bool isAtLeastKernelVersion(unsigned major, unsigned minor, unsigned sub) {
+static inline bool isAtLeastKernelVersion(unsigned major, unsigned minor,
+                                          unsigned sub) {
   return kernelVersion() >= KVER(major, minor, sub);
 }
 
-}
+} // namespace android