title: Adding GPIOLIB dependency
body: <p>I'm trying to compile a kernel module which uses the new GPIO API from <code>linux/gpio/consumer.h</code>. But the make fails with '<code>error: ‘gpio_handle’ has an incomplete type ‘struct gpio_desc’'</code>. I read that I need to additionally include GPIOLIB dependency in Kconfig, but simply adding 'depends on' doesn't work. What is the correct way to include such a dependency?</p>