iio: adc: ad7606: use gpiod_multi_set_value_cansleep

iio: adc: ad7606: use gpiod_multi_set_value_cansleep

Reduce verbosity by using gpiod_multi_set_value_cansleep() instead of
gpiod_set_array_value().

These are not called in an atomic context, so changing to the cansleep
variant is fine.

Also drop unnecessary braces while we are at it.

Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: David Lechner <dlechner@baylibre.com>
Link: https://patch.msgid.link/20250210-gpio-set-array-helper-v3-7-d6a673674da8@baylibre.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>