mfd: max77686: Convert to use regmap_irq

By using the generic IRQ support in the Register map API, it
is possible to get rid max77686-irq.c and simplify the code.

Suggested-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Reviewed-by: Doug Anderson <dianders@chromium.org>
Tested-by: Doug Anderson <dianders@chromium.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
index 4e2bc25..f001487 100644
--- a/drivers/mfd/Makefile
+++ b/drivers/mfd/Makefile
@@ -115,7 +115,7 @@
 obj-$(CONFIG_MFD_DA9063)	+= da9063.o
 
 obj-$(CONFIG_MFD_MAX14577)	+= max14577.o
-obj-$(CONFIG_MFD_MAX77686)	+= max77686.o max77686-irq.o
+obj-$(CONFIG_MFD_MAX77686)	+= max77686.o
 obj-$(CONFIG_MFD_MAX77693)	+= max77693.o
 obj-$(CONFIG_MFD_MAX8907)	+= max8907.o
 max8925-objs			:= max8925-core.o max8925-i2c.o