mfd: Make TPS6105X select REGMAP_I2C

This is required since
commit 7e507119 ("mfd: tps6105x: Use i2c regmap to access registers").
Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

drivers/mfd/Kconfig

@@ -1071,6 +1071,7 @@ config MFD_PALMAS
 config TPS6105X
 	tristate "TI TPS61050/61052 Boost Converters"
 	depends on I2C
+	select REGMAP_I2C
 	select REGULATOR
 	select MFD_CORE
 	select REGULATOR_FIXED_VOLTAGE