mfd: 88pm800: Initialize mask_invert

mask_invert must be set otherwise interrupts cannot be cleared.
Signed-off-by: Chao Xie <chao.xie@marvell.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

drivers/mfd/88pm800.c

@@ -362,6 +362,7 @@ static struct regmap_irq_chip pm800_irq_chip = {
 	.status_base = PM800_INT_STATUS1,
 	.mask_base = PM800_INT_ENA_1,
 	.ack_base = PM800_INT_STATUS1,
+	.mask_invert = 1,
 };
 
 static int pm800_pages_init(struct pm80x_chip *chip)