iio: pressure: bmp280: Use IS_ERR() in bmp280_common_probe()

`devm_gpiod_get_optional()` may return non-NULL error pointer on failure.
Check its return value using `IS_ERR()` and propagate the error if
necessary.

Fixes: df6e712 ("iio: pressure: bmp280: Explicitly mark GPIO optional")
Signed-off-by: Salah Triki <salah.triki@gmail.com>
Reviewed-by: David Lechner <dlechner@baylibre.com>
Link: https://patch.msgid.link/20250818092740.545379-2-salah.triki@gmail.com
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Author: salah-triki

drivers/iio/pressure/bmp280-core.c

@@ -3213,11 +3213,12 @@ int bmp280_common_probe(struct device *dev,
 
 	/* Bring chip out of reset if there is an assigned GPIO line */
 	gpiod = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
+	if (IS_ERR(gpiod))
+		return dev_err_probe(dev, PTR_ERR(gpiod), "failed to get reset GPIO\n");
+
 	/* Deassert the signal */
-	if (gpiod) {
-		dev_info(dev, "release reset\n");
-		gpiod_set_value(gpiod, 0);
-	}
+	dev_info(dev, "release reset\n");
+	gpiod_set_value(gpiod, 0);
 
 	data->regmap = regmap;