regulator: bq257xx: Make OTG enable GPIO really optional

The bindings describe the OTG enable GPIO as optional, but the driver
gets upset if it's not provided in the device tree.

Make the driver accept the absence of the GPIO, and just use register
writes to handle OTG mode in that case, skipping the error message for
-ENOENT.

Acked-by: Mark Brown <broonie@kernel.org>
Tested-by: Chris Morgan <macromorgan@hotmail.com>
Signed-off-by: Alexey Charkov <alchark@flipper.net>
Link: https://patch.msgid.link/20260331-bq25792-v6-4-0278fba33eb9@flipper.net
Signed-off-by: Mark Brown <broonie@kernel.org>

Author: alchark

drivers/regulator/bq257xx-regulator.c

@@ -127,6 +127,12 @@ static void bq257xx_reg_dt_parse_gpio(struct platform_device *pdev)
 	of_node_put(subchild);
 
 	if (IS_ERR(pdata->otg_en_gpio)) {
+		if (PTR_ERR(pdata->otg_en_gpio) == -ENOENT) {
+			/* No GPIO, will only use register writes for OTG */
+			pdata->otg_en_gpio = NULL;
+			return;
+		}
+
 		dev_err(&pdev->dev, "Error getting enable gpio: %ld\n",
 			PTR_ERR(pdata->otg_en_gpio));
 		return;