mfd: gateworks-gsc: 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 <aidanmacdonald.0x0@gmail.com>
Signed-off-by: Lee Jones <lee@kernel.org>
Link: https://lore.kernel.org/r/20221112151835.39059-5-aidanmacdonald.0x0@gmail.com

drivers/mfd/gateworks-gsc.c

@@ -189,8 +189,7 @@ static const struct regmap_irq_chip gsc_irq_chip = {
 	.num_irqs = ARRAY_SIZE(gsc_irqs),
 	.num_regs = 1,
 	.status_base = GSC_IRQ_STATUS,
-	.mask_base = GSC_IRQ_ENABLE,
-	.mask_invert = true,
+	.unmask_base = GSC_IRQ_ENABLE,
 	.ack_base = GSC_IRQ_STATUS,
 	.ack_invert = true,
 };