gpio: davinci: Validate the obtained number of IRQs

Value of pdata->gpio_unbanked is taken from Device Tree. In case of broken
DT due to any error this value can be any. Without this value validation
there can be out of chips->irqs array boundaries access in
davinci_gpio_probe().

Validate the obtained nirq value so that it won't exceed the maximum
number of IRQs per bank.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: eb3744a ("gpio: davinci: Do not assume continuous IRQ numbering")
Signed-off-by: Aleksandr Mishin <amishin@t-argos.ru>
Link: https://lore.kernel.org/r/20240618144344.16943-1-amishin@t-argos.ru
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

drivers/gpio/gpio-davinci.c

@@ -225,6 +225,11 @@ static int davinci_gpio_probe(struct platform_device *pdev)
  else
  nirq = DIV_ROUND_UP(ngpio, 16);
 
+ if (nirq > MAX_INT_PER_BANK) {
+ dev_err(dev, "Too many IRQs!\n");
+ return -EINVAL;
+ }
+
  chips = devm_kzalloc(dev, sizeof(*chips), GFP_KERNEL);
  if (!chips)
  return -ENOMEM;