backports: add ath10k defconfig

Signed-off-by: Luis R. Rodriguez <mcgrof@do-not-panic.com>
backports: add make help and defconfig-help targets

Throw users a bone by helping them compile specific target
drivers. Hauke did some good work in providing tons of
defconfigs, provide a command to let users query these
easily with 'make defconfig-help'. Also provide a more
generic 'make help' target.

Screenshot of make defconfig-help:

mcgrof@frijol ~/backports-20130618 $ make defconfig-help
Driver or subsystem configuration targets:
  defconfig-alx
  defconfig-ar5523
  defconfig-ath5k
  defconfig-ath6kl
  defconfig-ath9k
  defconfig-ath10k
  defconfig-b43
  defconfig-b43legacy
  defconfig-brcmfmac
  defconfig-brcmsmac
  defconfig-carl9170
  defconfig-drm
  defconfig-ieee802154
  defconfig-iwlwifi
  defconfig-media
  defconfig-nfc
  defconfig-regulator
  defconfig-rtlwifi
  defconfig-wifi
  defconfig-wil6210

Running 'make help' will provide the above and in addition to that
something similar to what the Linux kernel provides with the
list of supported targets backports provides.

Signed-off-by: Luis R. Rodriguez <mcgrof@do-not-panic.com>
backports: update README to include new subsystems

Signed-off-by: Luis R. Rodriguez <mcgrof@do-not-panic.com>
backports: Fix and document EXPORT_SYMBOL_GPL() preference

In terms of project naming the backports project has evolved
as follows:

compat-wireless --> compat-drivers --> backports

All along the design and intent behind the initial project
has been to provide a framework for delivery of *upstream*
drivers using a backported infrastructure. I've made it
clear that in no way shape or form did I ever want any
proprietary driver to make use of the framework. As the
project has grown I'm not alone with this sentiment so
lets document that and also fix a few symbols that have
slipped along the way.

Signed-off-by: Luis R. Rodriguez <mcgrof@do-not-panic.com>
backports: add gplizer for EXPORT_SYMBOL_GPL() help

If we forget to use EXPORT_SYMBOL_GPL() we can run this.
We may later use this for other things.

Signed-off-by: Luis R. Rodriguez <mcgrof@do-not-panic.com>