mfd: Allow to specify max77686 interrupt through DT or platform file also

Presently driver expects irq_gpio pin in platform data and maps it to irq
itself. But we can also directly specify the interrupt in DT or platform file.

Signed-off-by: Yadwinder Singh Brar <yadi.brar@samsung.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
diff --git a/drivers/mfd/max77686.c b/drivers/mfd/max77686.c
index 9e7e1d3..c66639d 100644
--- a/drivers/mfd/max77686.c
+++ b/drivers/mfd/max77686.c
@@ -77,6 +77,7 @@
 
 	max77686->wakeup = pdata->wakeup;
 	max77686->irq_gpio = pdata->irq_gpio;
+	max77686->irq = i2c->irq;
 
 	if (regmap_read(max77686->regmap,
 			 MAX77686_REG_DEVICE_ID, &data) < 0) {