gpiolib: devprop: Warn if gpio-line-names is too long

Some DT authors (including myself) have messed up the length of
gpio-line-names and made it longer than it should be. Add a warning here
so that developers can figure out that they've messed up their DT and
should fix it.

Cc: Alexandru M Stan <amstan@chromium.org>
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
diff --git a/drivers/gpio/gpiolib-devprop.c b/drivers/gpio/gpiolib-devprop.c
index 53781b2..2674103 100644
--- a/drivers/gpio/gpiolib-devprop.c
+++ b/drivers/gpio/gpiolib-devprop.c
@@ -37,8 +37,11 @@ void devprop_gpiochip_set_names(struct gpio_chip *chip,
 	if (count < 0)
 		return;
 
-	if (count > gdev->ngpio)
+	if (count > gdev->ngpio) {
+		dev_warn(&gdev->dev, "gpio-line-names is length %d but should be at most length %d",
+			 count, gdev->ngpio);
 		count = gdev->ngpio;
+	}
 
 	names = kcalloc(count, sizeof(*names), GFP_KERNEL);
 	if (!names)