Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/include/net/netns/hash.h b/include/net/netns/hash.h
index 16a8424..d9b6651 100644
--- a/include/net/netns/hash.h
+++ b/include/net/netns/hash.h
@@ -2,16 +2,10 @@
 #ifndef __NET_NS_HASH_H__
 #define __NET_NS_HASH_H__
 
-#include <asm/cache.h>
-
-struct net;
+#include <net/net_namespace.h>
 
 static inline u32 net_hash_mix(const struct net *net)
 {
-#ifdef CONFIG_NET_NS
-	return (u32)(((unsigned long)net) >> ilog2(sizeof(*net)));
-#else
-	return 0;
-#endif
+	return net->hash_mix;
 }
 #endif