gpio/aspeed: Fix incorrect number of banks

The current calculation for the number of GPIO banks is only correct if
the number of GPIOs is a multiple of 32 (if there were 31 GPIOs we would
currently say there are 0 banks, which is incorrect).

Fixes: 361b79119a ('gpio: Add Aspeed driver')

Signed-off-by: Rashmica Gupta <rashmica.g@gmail.com>
Reviewed-by: Andrew Jeffery <andrew@aj.id.au>
Link: https://lore.kernel.org/r/20190906062623.13354-1-rashmica.g@gmail.com
Reviewed-by: Joel Stanley <joel@jms.d.au>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/gpio/gpio-aspeed.c

@@ -1168,7 +1168,7 @@ static int __init aspeed_gpio_probe(struct platform_device *pdev)
 	gpio->chip.base = -1;
 
 	/* Allocate a cache of the output registers */
-	banks = gpio->config->nr_gpios >> 5;
+	banks = DIV_ROUND_UP(gpio->config->nr_gpios, 32);
 	gpio->dcache = devm_kcalloc(&pdev->dev,
 				    banks, sizeof(u32), GFP_KERNEL);
 	if (!gpio->dcache)