mtd: rawnand: lpc32xx_slc: Convert to use devm_gpiod_get_optional()

The initial fix for a GPIO descriptor leak added manual gpiod_put()
calls in the error path and remove function.

This follow-up patch improves upon the fix by switching to the
resource-managed devm_gpiod_get_optional() API.

Suggested-by: Vladimir Zapolskiy <vz@mleia.com>
Signed-off-by: Haotian Zhang <vulab@iscas.ac.cn>
Reviewed-by: Vladimir Zapolskiy <vz@mleia.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>

Author: ISCAS-Vulab

drivers/mtd/nand/raw/lpc32xx_slc.c

@@ -854,7 +854,7 @@ static int lpc32xx_nand_probe(struct platform_device *pdev)
 	}
 
 	/* Start with WP disabled, if available */
-	host->wp_gpio = gpiod_get_optional(&pdev->dev, NULL, GPIOD_OUT_LOW);
+	host->wp_gpio = devm_gpiod_get_optional(&pdev->dev, NULL, GPIOD_OUT_LOW);
 	res = PTR_ERR_OR_ZERO(host->wp_gpio);
 	if (res) {
 		if (res != -EPROBE_DEFER)
@@ -937,7 +937,6 @@ static int lpc32xx_nand_probe(struct platform_device *pdev)
 	dma_release_channel(host->dma_chan);
 enable_wp:
 	lpc32xx_wp_enable(host);
-	gpiod_put(host->wp_gpio);
 
 	return res;
 }
@@ -963,7 +962,6 @@ static void lpc32xx_nand_remove(struct platform_device *pdev)
 	writel(tmp, SLC_CTRL(host->io_base));
 
 	lpc32xx_wp_enable(host);
-	gpiod_put(host->wp_gpio);
 }
 
 static int lpc32xx_nand_resume(struct platform_device *pdev)