drivers: iio: dac: ad5592r: add gpio_chip names

Add array of explicit gpio names for the `gpiochip` structure of
ad5592r, mainly for debug purposes.

Since the gpios are configurable via the dts, generic names are
used.
Signed-off-by: Antoniu Miclaus <antoniu.miclaus@analog.com>
Link: https://lore.kernel.org/r/20221117090130.51702-1-antoniu.miclaus@analog.comSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/dac/ad5592r-base.c

@@ -124,6 +124,10 @@ static int ad5592r_gpio_request(struct gpio_chip *chip, unsigned offset)
 	return 0;
 }
 
+static const char * const ad5592r_gpio_names[] = {
+	"GPIO0", "GPIO1", "GPIO2", "GPIO3", "GPIO4", "GPIO5", "GPIO6", "GPIO7",
+};
+
 static int ad5592r_gpio_init(struct ad5592r_state *st)
 {
 	if (!st->gpio_map)
@@ -140,6 +144,7 @@ static int ad5592r_gpio_init(struct ad5592r_state *st)
 	st->gpiochip.set = ad5592r_gpio_set;
 	st->gpiochip.request = ad5592r_gpio_request;
 	st->gpiochip.owner = THIS_MODULE;
+	st->gpiochip.names = ad5592r_gpio_names;
 
 	mutex_init(&st->gpio_lock);