mfd: Use regmap for tps6586x register access.

Using regmap apis for accessing the device registers.

Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
Reviewed-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 b9deb17..6258bf0 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@@ -200,6 +200,7 @@
 	bool "TPS6586x Power Management chips"
 	depends on I2C=y && GPIOLIB && GENERIC_HARDIRQS
 	select MFD_CORE
+	select REGMAP_I2C
 	depends on REGULATOR
 	help
 	  If you say yes here you get support for the TPS6586X series of