ar71xx: add kernel support for dir-835-a1

ar71xx: add kernel support for dir-835-a1

[juhosg:
  - remove custom mdio bus info and platform data for ar8327, clear the
    .led_cfg field from dir835a1_setup instead,
  - remove arguments of dir835c1_generic_setup function, register the
    LEDs directly from the board specific setup instead]

Signed-off-by: Alexander Stadler <sa.maillists@univie.ac.at>
Patchwork: http://patchwork.openwrt.org/patch/3426/
Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
git-svn-id: svn://svn.openwrt.org/openwrt/trunk@35957 3c298f89-4303-0410-b956-a3cf2f4a3e73