pinctrl: aspeed: Force to disable the function's signal

When the driver want to disable the signal of the function, it doesn't
need to query the state of the mux function's signal on a pin. The
condition below will miss the disable of the signal:
Ball | Default | P0 Signal | P0 Expression               | Other
-----+---------+-----------+-----------------------------+----------
 E21   GPIOG0    SD2CLK      SCU4B4[16]=1 & SCU450[1]=1    GPIOG0
-----+---------+-----------+-----------------------------+----------
 B22   GPIOG1    SD2CMD      SCU4B4[17]=1 & SCU450[1]=1    GPIOG1
-----+---------+-----------+-----------------------------+----------
Assume the register status like below:
SCU4B4[16] == 1 & SCU4B4[17] == 1 & SCU450[1]==1
After the driver set the Ball E21 to the GPIOG0:
SCU4B4[16] == 0 & SCU4B4[17] == 1 & SCU450[1]==0
When the driver want to set the Ball B22 to the GPIOG1, the condition of
the SD2CMD will be false causing SCU4B4[17] not to be cleared.

Signed-off-by: Billy Tsai <billy_tsai@aspeedtech.com>
Acked-by: Andrew Jeffery <andrew@aj.id.au>
Link: https://lore.kernel.org/r/20220818101839.28860-1-billy_tsai@aspeedtech.com
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/pinctrl/aspeed/pinctrl-aspeed.c

@@ -92,19 +92,10 @@ static int aspeed_sig_expr_enable(struct aspeed_pinmux_data *ctx,
 static int aspeed_sig_expr_disable(struct aspeed_pinmux_data *ctx,
 				   const struct aspeed_sig_expr *expr)
 {
-	int ret;
-
 	pr_debug("Disabling signal %s for %s\n", expr->signal,
 		 expr->function);
 
-	ret = aspeed_sig_expr_eval(ctx, expr, true);
-	if (ret < 0)
-		return ret;
-
-	if (ret)
-		return aspeed_sig_expr_set(ctx, expr, false);
-
-	return 0;
+	return aspeed_sig_expr_set(ctx, expr, false);
 }
 
 /**