mfd: da9063: Get irq base dynamically before registering device

After registering mfd device with proper irq_base
platform_get_irq_byname() calls will return VIRQ instead of local IRQ.
This fixes da9063 rtc registration issue:
da9063-rtc da9063-rtc: Failed to request ALARM IRQ 1: -22
Signed-off-by: Dmitry Lavnikevich <d.lavnikevich@sam-solutions.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

drivers/mfd/da9063-core.c

@@ -118,7 +118,7 @@ int da9063_device_init(struct da9063 *da9063, unsigned int irq)
 		da9063->irq_base = pdata->irq_base;
 	} else {
 		da9063->flags = 0;
-		da9063->irq_base = 0;
+		da9063->irq_base = -1;
 	}
 	da9063->chip_irq = irq;
 
@@ -168,6 +168,8 @@ int da9063_device_init(struct da9063 *da9063, unsigned int irq)
 		return ret;
 	}
 
+	da9063->irq_base = regmap_irq_chip_get_base(da9063->regmap_irq);
+
 	ret = mfd_add_devices(da9063->dev, -1, da9063_devs,
 			      ARRAY_SIZE(da9063_devs), NULL, da9063->irq_base,
 			      NULL);