gpio: sifive: Fix SiFive gpio probe

Fix the check on the number of IRQs to allow up to the maximum (32)
instead of only the maximum minus one.

Fixes: 96868dce ("gpio/sifive: Add GPIO driver for SiFive SoCs")
Cc: stable@vger.kernel.org
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Link: https://lore.kernel.org/r/20201107081420.60325-10-damien.lemoal@wdc.comSigned-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/gpio/gpio-sifive.c

@@ -183,7 +183,7 @@ static int sifive_gpio_probe(struct platform_device *pdev)
 		return PTR_ERR(chip->regs);
 
 	ngpio = of_irq_count(node);
-	if (ngpio >= SIFIVE_GPIO_MAX) {
+	if (ngpio > SIFIVE_GPIO_MAX) {
 		dev_err(dev, "Too many GPIO interrupts (max=%d)\n",
 			SIFIVE_GPIO_MAX);
 		return -ENXIO;