staging: dgap: remove unused configuration

The IO configuration was not used to configure the board. It was only
read from the configuration file. Stop reading it and also remove the
other related variables defined for it.

Signed-off-by: Sudip Mukherjee <sudip@vectorindia.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>