dt-bindings: hwmon: Add tmp75b to lm75.txt

Update the LM75's devicetree definition to allow Texas Instruments
TMP75B be probed.

Signed-off-by: Iker Perez del Palomar Sustatxa <iker.perez@codethink.co.uk>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

Documentation/devicetree/bindings/hwmon/lm75.txt

@@ -25,6 +25,7 @@ Required properties:
 		"ti,tmp175",
 		"ti,tmp275",
 		"ti,tmp75",
+		"ti,tmp75b",
 		"ti,tmp75c",
 
 - reg: I2C bus address of the device