dt-bindings: iio: adc: ti,ads1015: Add missing ADS1115 compatible string

Add missing ti,ads1115 compatible string. This compatible string is
supported by the Linux kernel driver and the ads1015 is a 12bit ADC
while ads1115 is 16bit ADC. Add the missing compatible string.
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Daniel Baluta <daniel.baluta@nxp.com>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: devicetree@vger.kernel.org
Reviewed-by: Andy Shevchenko <andy@kernel.org>
Link: https://lore.kernel.org/r/20220328194725.149150-1-marex@denx.deSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Documentation/devicetree/bindings/iio/adc/ti,ads1015.yaml

@@ -4,7 +4,7 @@
 $id: http://devicetree.org/schemas/iio/adc/ti,ads1015.yaml#
 $schema: http://devicetree.org/meta-schemas/core.yaml#
 
-title: TI ADS1015 4 channel I2C analog to digital converter
+title: TI ADS1015/ADS1115 4 channel I2C analog to digital converter
 
 maintainers:
   - Daniel Baluta <daniel.baluta@nxp.com>
@@ -15,7 +15,9 @@ description: |
 
 properties:
   compatible:
-    const: ti,ads1015
+    enum:
+      - ti,ads1015
+      - ti,ads1115
 
   reg:
     maxItems: 1