KEYS:  Fix the comment to match the file name in rxrpc-type.h.

Signed-off-by: Robert P. J. Day <rpjday@crashcourse.ca>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com>
diff --git a/include/keys/rxrpc-type.h b/include/keys/rxrpc-type.h
index 4ea429b..7609365 100644
--- a/include/keys/rxrpc-type.h
+++ b/include/keys/rxrpc-type.h
@@ -21,4 +21,4 @@
 
 extern struct key *rxrpc_get_null_key(const char *);
 
-#endif /* _KEYS_USER_TYPE_H */
+#endif /* _KEYS_RXRPC_TYPE_H */