mfd: rn5t618: 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/20221112151835.39059-10-aidanmacdonald.0x0@gmail.com

drivers/mfd/rn5t618.c

@@ -80,8 +80,7 @@ static const struct regmap_irq_chip rc5t619_irq_chip = {
 	.num_irqs = ARRAY_SIZE(rc5t619_irqs),
 	.num_regs = 1,
 	.status_base = RN5T618_INTMON,
-	.mask_base = RN5T618_INTEN,
-	.mask_invert = true,
+	.unmask_base = RN5T618_INTEN,
 };
 
 static struct i2c_client *rn5t618_pm_power_off;