regulator: gpio: Fix the out-of-bounds access to drvdata::gpiods

drvdata::gpiods is supposed to hold an array of 'gpio_desc' pointers. But
the memory is allocated for only one pointer. This will lead to
out-of-bounds access later in the code if 'config::ngpios' is > 1. So
fix the code to allocate enough memory to hold 'config::ngpios' of GPIO
descriptors.

While at it, also move the check for memory allocation failure to be below
the allocation to make it more readable.

Cc: [e-mail] # 5.0
Fixes: d6cd33ad7102 ("regulator: gpio: Convert to use descriptors")
Signed-off-by: Manivannan Sadhasivam <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Mark Brown <[e-mail]>

drivers/regulator/gpio-regulator.c

···
 		return -ENOMEM;
 	}
 
-	drvdata->gpiods = devm_kzalloc(dev, sizeof(struct gpio_desc *),
-				       GFP_KERNEL);
+	drvdata->gpiods = devm_kcalloc(dev, config->ngpios,
+				       sizeof(struct gpio_desc *), GFP_KERNEL);
+	if (!drvdata->gpiods)
+		return -ENOMEM;
 
 	if (config->input_supply) {
 		drvdata->desc.supply_name = devm_kstrdup(&pdev->dev,
···
 		}
 	}
 
-	if (!drvdata->gpiods)
-		return -ENOMEM;
 	for (i = 0; i < config->ngpios; i++) {
 		drvdata->gpiods[i] = devm_gpiod_get_index(dev,
 							  NULL,