iio: adc: ad7766: Remove unneeded gpiod NULL check

The gpiod API checks for NULL descriptors, so there is no need to
duplicate the check in the driver.

Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
1 file changed