hwmon: (emc1403) Fix missing 'select REGMAP_I2C' in Kconfig

In commit 4cab259f, the emc1403 driver was converted to use regmap but the
necessary Kconfig option was not added.

Signed-off-by: Josef Gajdusek <atx@atx.name>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index 154851b..02d3d85 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -1177,6 +1177,7 @@
 config SENSORS_EMC1403
 	tristate "SMSC EMC1403/23 thermal sensor"
 	depends on I2C
+	select REGMAP_I2C
 	help
 	  If you say yes here you get support for the SMSC EMC1403/23
 	  temperature monitoring chip.