staging: comedi: contec_pci_dio: remove thisboard macro

This macro relies on a local variable of a specific name. Remove the
macro and use the comedi_board() helper to get the thisboard pointer.

Move the 'dev->board_name = thisboard->name;' in contec_attach().
The contec_find_pci_dev() function modifies the dev->board_ptr.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>