staging: comedi: dnya_pci10xx: remove thisboard and devpriv macros

These macros rely on local variables having a specific name. Replace
them with local variables where used. Use the comedi_board() helper
to get the thisboard pointer.

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>