iio: adc: ad7606: fix standby gpio state to match the documentation
The binding's documentation specifies that "As the line is active low, it
should be marked GPIO_ACTIVE_LOW". However, in the driver, it was handled
the opposite way. This commit sets the driver's behaviour in sync with the
documentation
Fixes: 722407a4e8c0 ("staging:iio:ad7606: Use GPIO descriptor API") Signed-off-by: Guillaume Stols <gstols@baylibre.com> Reviewed-by: Nuno Sa <nuno.sa@analog.com> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>