staging: dgap: Simplify to set a concentrator type

It is same manner with setting a board type.
For example of config file for concentrator,
    "conc ccon" or
    "conc epcon"

After allocating a type of "CNODE" then set a type of concentrator.
So remove cases in swith statement, just get a token from string
and set to "conc.type". And also it doesn't need to "conc.v_type".

Signed-off-by: Daeseok Youn <daeseok.youn@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>