ACPI / gpio: avoid warning for gpio hogging code

The newly added acpi_gpiochip_scan_gpios function produces a few harmless
warnings:

drivers/gpio/gpiolib-acpi.c: In function ‘acpi_gpiochip_add’:
drivers/gpio/gpiolib-acpi.c:925:7: error: ‘dflags’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
drivers/gpio/gpiolib-acpi.c:925:9: error: ‘lflags’ may be used uninitialized in this function [-Werror=maybe-uninitialized]

The problem is that he compiler cannot know that a negative return value
from fwnode_property_read_u32_array() or acpi_gpiochip_pin_to_gpio_offset()
implies that the IS_ERR(gpio_desc) is true, as the value could in theory
be below -MAX_ERRNO.

The function already initializes its output values to zero, and moving
that intialization a little higher up ensures that we can never have
uninitialized data in the caller.

Fixes: c80f1ba75d ("ACPI / gpio: Add hogging support")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/gpio/gpiolib-acpi.c

@@ -866,6 +866,10 @@ static struct gpio_desc *acpi_gpiochip_parse_own_gpio(
 	u32 gpios[2];
 	int ret;
 
+	*lflags = 0;
+	*dflags = 0;
+	*name = NULL;
+
 	ret = fwnode_property_read_u32_array(fwnode, "gpios", gpios,
 					     ARRAY_SIZE(gpios));
 	if (ret < 0)
@@ -879,10 +883,6 @@ static struct gpio_desc *acpi_gpiochip_parse_own_gpio(
 	if (IS_ERR(desc))
 		return desc;
 
-	*lflags = 0;
-	*dflags = 0;
-	*name = NULL;
-
 	if (gpios[1])
 		*lflags |= GPIO_ACTIVE_LOW;