module: make module param bint handle nul value

Allow bint param accept nul values, just do same as bool param.
Signed-off-by: Dave Young <dyoung@redhat.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

kernel/params.c

@@ -97,7 +97,8 @@ static int parse_one(char *param,
 	for (i = 0; i < num_params; i++) {
 		if (parameq(param, params[i].name)) {
 			/* No one handled NULL, so do it here. */
-			if (!val && params[i].ops->set != param_set_bool)
+			if (!val && params[i].ops->set != param_set_bool
+			    && params[i].ops->set != param_set_bint)
 				return -EINVAL;
 			pr_debug("They are equal!  Calling %p\n",
 			       params[i].ops->set);