gpio: max77620: Add missing dependency on GPIOLIB_IRQCHIP

Driver fails to compile in a minimized kernel's configuration because of
the missing dependency on GPIOLIB_IRQCHIP.

 error: ‘struct gpio_chip’ has no member named ‘irq’
   44 |   virq = irq_find_mapping(gpio->gpio_chip.irq.domain, offset);

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Link: https://lore.kernel.org/r/20200106015154.12040-1-digetx@gmail.com
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/gpio/Kconfig

@@ -1148,6 +1148,7 @@ config GPIO_MADERA
 config GPIO_MAX77620
 	tristate "GPIO support for PMIC MAX77620 and MAX20024"
 	depends on MFD_MAX77620
+	select GPIOLIB_IRQCHIP
 	help
 	  GPIO driver for MAX77620 and MAX20024 PMIC from Maxim Semiconductor.
 	  MAX77620 PMIC has 8 pins that can be configured as GPIOs. The