mfd: max77693: Handle IRQs using regmap

This patch modifies mfd driver to use regmap for handling interrupts.
It allows to simplify irq handling process. This modifications needed
to make small changes in function drivers, which use interrupts.

Signed-off-by: Robert Baldyga <r.baldyga@samsung.com>
Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Acked-by: Chanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index ee8204c..2feac14 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@@ -384,6 +384,7 @@
 	depends on I2C=y
 	select MFD_CORE
 	select REGMAP_I2C
+	select REGMAP_IRQ
 	help
 	  Say yes here to add support for Maxim Semiconductor MAX77693.
 	  This is a companion Power Management IC with Flash, Haptic, Charger,