staging: dgap: Simplify to set a module type

It is same manner with setting a board type.
After allocating a type of "MNODE", get a token value
set to "module.type".

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