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>

include/keys/rxrpc-type.h

@@ -21,4 +21,4 @@ extern struct key_type key_type_rxrpc;
 
 extern struct key *rxrpc_get_null_key(const char *);
 
-#endif /* _KEYS_USER_TYPE_H */
+#endif /* _KEYS_RXRPC_TYPE_H */