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 --cc drivers/mfd/Kconfig
Simple merge

diff --cc drivers/mfd/tps6586x.c
Simple merge