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.de


Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>