iio:light:stk3310: Fix REGMAP_I2C dependency

The stk3310 driver makes use of regmap_i2c, so this dependency needs to be
reflected in Kconfig.
Signed-off-by: NHartmut Knaack <knaack.h@gmx.de>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

drivers/iio/light/Kconfig

@@ -201,6 +201,7 @@ config LTR501
 config STK3310
 	tristate "STK3310 ALS and proximity sensor"
 	depends on I2C
+	select REGMAP_I2C
 	help
 	 Say yes here to get support for the Sensortek STK3310 ambient light
 	 and proximity sensor. The STK3311 model is also supported by this