pinctrl: aspeed: Fix confusing types in return value

The function signature is int, but we return a bool. Instead return a
negative errno as the kerneldoc suggests.

Fixes: 4d3d0e42 ("pinctrl: Add core support for Aspeed SoCs")
Signed-off-by: NJoel Stanley <joel@jms.id.au>
Reviewed-by: NAndrew Jeffery <andrew@aj.id.au>
Link: https://lore.kernel.org/r/20230119231856.52014-1-joel@jms.id.auSigned-off-by: NLinus Walleij <linus.walleij@linaro.org>

drivers/pinctrl/aspeed/pinctrl-aspeed.c

@@ -114,7 +114,7 @@ static int aspeed_disable_sig(struct aspeed_pinmux_data *ctx,
 	int ret = 0;
 
 	if (!exprs)
-		return true;
+		return -EINVAL;
 
 	while (*exprs && !ret) {
 		ret = aspeed_sig_expr_disable(ctx, *exprs);