gpiolib: of: Drop redundant check in of_mm_gpiochip_remove()

The callers never call the function with invalid pointer.
Moreover, compiler quite likely dropped that check anyway
because we use that pointer before the check.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

drivers/gpio/gpiolib-of.c

@@ -961,9 +961,6 @@ void of_mm_gpiochip_remove(struct of_mm_gpio_chip *mm_gc)
 {
 	struct gpio_chip *gc = &mm_gc->gc;
 
-	if (!mm_gc)
-		return;
-
 	gpiochip_remove(gc);
 	iounmap(mm_gc->regs);
 	kfree(gc->label);