irqchip/sl28cpld: Replace irqchip mask_invert with unmask_base

Remove use of the deprecated mask_invert flag. Inverted mask
registers (where a '1' bit enables an IRQ) can be described more
directly as an unmask register.

Signed-off-by: Aidan MacDonald <[e-mail]>
Reviewed-by: Michael Walle <[e-mail]>
Signed-off-by: Marc Zyngier <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

drivers/irqchip/irq-sl28cpld.c

···
 	irqchip->chip.num_irqs = ARRAY_SIZE(sl28cpld_irqs);
 	irqchip->chip.num_regs = 1;
 	irqchip->chip.status_base = base + INTC_IP;
-	irqchip->chip.mask_base = base + INTC_IE;
-	irqchip->chip.mask_invert = true;
+	irqchip->chip.unmask_base = base + INTC_IE;
 	irqchip->chip.ack_base = base + INTC_IP;
 
 	return devm_regmap_add_irq_chip_fwnode(dev, dev_fwnode(dev),