The IRQCHIP implementation used inside the gpiochips are not supposed to
be changed during runtime. So let's make the one inside the spmi-gpio
gpiochip immutable.
This fixes the below warning during boot:
gpio gpiochip0: (c440000.spmi:pmic@0:gpio@c000): not an immutable
chip, please consider fixing it!
Separate callbacks need to be provided for irq_{mask/unmask} pointers since
the callbacks are supposed to mask/unmask the corresponding parent IRQ in
addition to changing the gpio_desc flags.
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx>