gpio: modify sysfs gpio export so that "value" displays as 0 or 1

gpiolib can export GPIOs to userspace via sysfs.  This patch modifies the
gpio_value_show() so that any non-zero value is explicitly printed as "1",
rather than whatever numerical value the lower-level driver returns.
Signed-off-by: Steve Falco <sfalco@harris.com>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/gpio/gpiolib.c

@@ -248,7 +248,7 @@ static ssize_t gpio_value_show(struct device *dev,
 	if (!test_bit(FLAG_EXPORT, &desc->flags))
 		status = -EIO;
 	else
-		status = sprintf(buf, "%d\n", gpio_get_value_cansleep(gpio));
+		status = sprintf(buf, "%d\n", !!gpio_get_value_cansleep(gpio));
 
 	mutex_unlock(&sysfs_lock);
 	return status;