dt-bindings: hwmon: ina2xx: Describe ina260 chip

Describe ina260 chip which is precision digital current and power monitor
with precision integrated shunt resistor.
Signed-off-by: Michal Simek <michal.simek@amd.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/4c82dc4d412e91d1601c1da5bca1cdf1a91cd9b8.1704724242.git.michal.simek@amd.comSigned-off-by: Guenter Roeck <linux@roeck-us.net>

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

@@ -28,6 +28,7 @@ properties:
       - ti,ina231
       - ti,ina237
       - ti,ina238
+      - ti,ina260
 
   reg:
     maxItems: 1