kernel: adm6996: add support for ADM6996L and GPIO interface

This patch makes it possible to use adm6996.c on first generation 
BCM47XX devices with ADM switches.
The GPIO bit banging protocol implementation was copied from the old 
switch driver and adapted to this driver and changed to the mainline 
kernel GPIO interface.
The ADM6996L is different from the ADM6996M which is supported, for 
both specs are available in the Internet.

This was tested on a WRT54GS version 1.0, thank you Dirk Neukirchen for 
the device.

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>


git-svn-id: svn://svn.openwrt.org/openwrt/trunk@38698 3c298f89-4303-0410-b956-a3cf2f4a3e73
brcm47xx: register ADM6996L switch

This patch makes it possible to use adm6996.c on first generation 
BCM47XX devices with ADM switches.

This was tested on a WRT54GS version 1.0, thank you Dirk Neukirchen for 
the device.

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>


git-svn-id: svn://svn.openwrt.org/openwrt/trunk@38699 3c298f89-4303-0410-b956-a3cf2f4a3e73