module: mark arguments used

Reviewed-by: Alejandro Colomar <alx.manpages@gmail.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ahelenia Ziemiańska <nabijaczleweli@nabijaczleweli.xyz>
Closes #13110

module/os/freebsd/spl/callb.c

@@ -338,10 +338,10 @@ callb_generic_cpr(void *arg, int code)
  * The generic callback function associated with kernel threads which
  * are always considered safe.
  */
-/* ARGSUSED */
 boolean_t
 callb_generic_cpr_safe(void *arg, int code)
 {
+	(void) arg, (void) code;
 	return (B_TRUE);
 }
 /*