mfd: Add irq domain support for max8997 interrupts

Add irq domain support for max8997 interrupts. The reverse mapping method
used is linear mapping since the sub-drivers of max8997 such as regulator
and charger drivers can use the max8997 irq_domain to get the linux irq
number for max8997 interrupts. All uses of irq_base in platform data and
max8997 driver private data are removed.

Reviwed-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: MyungJoo Ham <myungjoo.ham@samsung.com>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Thomas Abraham <thomas.abraham@linaro.org>
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
diff --git a/include/linux/mfd/max8997-private.h b/include/linux/mfd/max8997-private.h
index 3f4deb6..830152c 100644
--- a/include/linux/mfd/max8997-private.h
+++ b/include/linux/mfd/max8997-private.h
@@ -23,6 +23,8 @@
 #define __LINUX_MFD_MAX8997_PRIV_H
 
 #include <linux/i2c.h>
+#include <linux/export.h>
+#include <linux/irqdomain.h>
 
 #define MAX8997_REG_INVALID	(0xff)
 
@@ -325,7 +327,7 @@
 
 	int irq;
 	int ono;
-	int irq_base;
+	struct irq_domain *irq_domain;
 	struct mutex irqlock;
 	int irq_masks_cur[MAX8997_IRQ_GROUP_NR];
 	int irq_masks_cache[MAX8997_IRQ_GROUP_NR];