mfd: Update irq handler in max8925

Update thread irq handler. Simply the interface of using thread irq.

Signed-off-by: Haojian Zhuang <haojian.zhuang@marvell.com>
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index 64fbe33..84a68d2 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@@ -204,8 +204,8 @@
 	  under the corresponding menus.
 
 config MFD_MAX8925
-	tristate "Maxim Semiconductor MAX8925 PMIC Support"
-	depends on I2C
+	bool "Maxim Semiconductor MAX8925 PMIC Support"
+	depends on I2C=y
 	select MFD_CORE
 	help
 	  Say yes here to support for Maxim Semiconductor MAX8925. This is