gpiolib: Introduce GPIO_LOOKUP_FLAGS_DEFAULT

Since GPIO library operates with enumerator when it's subject to handle
the GPIO lookup flags, it will be better to clearly see what default means.

Thus, introduce GPIO_LOOKUP_FLAGS_DEFAULT entry to describe
the default assumptions.

While here, replace 0 by newly introduced constant.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index e9909c0..b8e4c9c 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -2515,6 +2515,7 @@
 					    const char *label,
 					    enum gpiod_flags flags)
 {
+	unsigned long lflags = GPIO_LOOKUP_FLAGS_DEFAULT;
 	struct gpio_desc *desc = gpiochip_get_desc(chip, hwnum);
 	int err;
 
@@ -2527,7 +2528,7 @@
 	if (err < 0)
 		return ERR_PTR(err);
 
-	err = gpiod_configure_flags(desc, label, 0, flags);
+	err = gpiod_configure_flags(desc, label, lflags, flags);
 	if (err) {
 		chip_err(chip, "setup of own GPIO %s failed\n", label);
 		gpiod_free_commit(desc);
@@ -4162,7 +4163,7 @@
 					       unsigned int idx,
 					       enum gpiod_flags flags)
 {
-	unsigned long lookupflags = 0;
+	unsigned long lookupflags = GPIO_LOOKUP_FLAGS_DEFAULT;
 	struct gpio_desc *desc = NULL;
 	int status;
 	/* Maybe we have a device name, maybe not */
@@ -4249,8 +4250,8 @@
 					 enum gpiod_flags dflags,
 					 const char *label)
 {
+	unsigned long lflags = GPIO_LOOKUP_FLAGS_DEFAULT;
 	struct gpio_desc *desc;
-	unsigned long lflags = 0;
 	enum of_gpio_flags flags;
 	bool active_low = false;
 	bool single_ended = false;
@@ -4328,8 +4329,8 @@
 					 enum gpiod_flags dflags,
 					 const char *label)
 {
+	unsigned long lflags = GPIO_LOOKUP_FLAGS_DEFAULT;
 	struct gpio_desc *desc = ERR_PTR(-ENODEV);
-	unsigned long lflags = 0;
 	int ret;
 
 	if (!fwnode)