mfd: Add MAX8998 interrupts support

Use genirq and provide seperated file for interrupts support.

Signed-off-by: Joonyoung Shim <jy0922.shim@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
index feaeeae..b1ad74d 100644
--- a/drivers/mfd/Makefile
+++ b/drivers/mfd/Makefile
@@ -58,7 +58,7 @@
 obj-$(CONFIG_PMIC_DA903X)	+= da903x.o
 max8925-objs			:= max8925-core.o max8925-i2c.o
 obj-$(CONFIG_MFD_MAX8925)	+= max8925.o
-obj-$(CONFIG_MFD_MAX8998)	+= max8998.o
+obj-$(CONFIG_MFD_MAX8998)	+= max8998.o max8998-irq.o
 
 pcf50633-objs			:= pcf50633-core.o pcf50633-irq.o
 obj-$(CONFIG_MFD_PCF50633)	+= pcf50633.o