gpiolib: remove a redundant check in gpiod_to_chip()

This non-functional change slightly simplifies the implementation
of gpiod_to_chip() function.

Signed-off-by: Vladimir Zapolskiy <vz@mleia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 02cf658..c23cc6b 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -161,7 +161,7 @@
  */
 struct gpio_chip *gpiod_to_chip(const struct gpio_desc *desc)
 {
-	if (!desc || !desc->gdev || !desc->gdev->chip)
+	if (!desc || !desc->gdev)
 		return NULL;
 	return desc->gdev->chip;
 }