dt-bindings: hwmon: ti,ina2xx: Document ti,ina238 compatible string

Document the compatible string for the Texas Instruments INA238, this
device is a variant of the existing INA2xx devices and has the same
device tree bindings (shunt resistor).
Signed-off-by: Nathan Rossi <nathan.rossi@digi.com>
Acked-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20211102052754.817220-1-nathan@nathanrossi.comSigned-off-by: Guenter Roeck <linux@roeck-us.net>

Documentation/devicetree/bindings/hwmon/ti,ina2xx.yaml

@@ -26,6 +26,7 @@ properties:
       - ti,ina226
       - ti,ina230
       - ti,ina231
+      - ti,ina238
 
   reg:
     maxItems: 1