Also import related functions gpio_request_one() and
gpio_free_array().

This commit imports code from linux 3.7 as
the more recent linux kernel versions use gpiolib descriptors,
see this commit for details:

  commit 372e722
  Author: Alexandre Courbot <acourbot@nvidia.com>
  Date:   Sun Feb 3 01:29:29 2013 +0900

      gpiolib: use descriptors internally

      Make sure gpiolib works internally with descriptors and (chip, offset)
      pairs instead of using the global integer namespace. This prepares the
      ground for the removal of the global gpio_desc[] array and the
      introduction of the descriptor-based GPIO API.

Signed-off-by: Antony Pavlov <antonynpavlov@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>