DT: i2c: Add ADS7828 and ADS7830 to list of trivial devices

This adds devicetree documentation for the bindings of the
ads7828 driver.
Signed-off-by: NDenis Carikli <denis@eukrea.com>
Acked-by: NGuenter Roeck <linux@roeck-us.net>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Documentation/devicetree/bindings/i2c/trivial-devices.txt

@@ -95,6 +95,8 @@ stm,m41t00		Serial Access TIMEKEEPER
 stm,m41t62		Serial real-time clock (RTC) with alarm
 stm,m41t80		M41T80 - SERIAL ACCESS RTC WITH ALARMS
 taos,tsl2550		Ambient Light Sensor with SMBUS/Two Wire Serial Interface
+ti,ads7828		8-Channels, 12-bit ADC
+ti,ads7830		8-Channels, 8-bit ADC
 ti,tsc2003		I2C Touch-Screen Controller
 ti,tmp102		Low Power Digital Temperature Sensor with SMBUS/Two Wire Serial Interface
 ti,tmp103		Low Power Digital Temperature Sensor with SMBUS/Two Wire Serial Interface