mfd: Convert pcf50633 to use new register map API

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Tested-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index 21574bd..13f0040 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@@ -500,6 +500,7 @@
 config MFD_PCF50633
 	tristate "Support for NXP PCF50633"
 	depends on I2C
+	select REGMAP_I2C
 	help
 	  Say yes here if you have NXP PCF50633 chip on your board.
 	  This core driver provides register access and IRQ handling