gpio: nomadik: handle variadic GPIO count

Read the "ngpios" property to determine the number of GPIOs for a bank.
If not available, fallback to NMK_GPIO_PER_CHIP ie 32 ie the current
behavior.

The IP block always supports 32 GPIOs, but platforms can expose a lesser
amount. The Mobileye EyeQ5 is in this case; one bank is 29 GPIOs and
the other is 23.

Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Théo Lebrun <theo.lebrun@bootlin.com>
Link: https://lore.kernel.org/r/20240228-mbly-gpio-v2-23-3ba757474006@bootlin.com


Signed-off-by: Linus Walleij <linus.walleij@linaro.org>