staging: comedi: 8255_pci: remove include of mite.h

The mite.h header is included only to pickup the MITE_IODWBSR and WENAB defines
needed to set the data window (PCI BAR 1) when initializing the PCI MITE ASIC
on the National Instruments boards supported by this driver.

Remove the include of mite.h by adding the two defines locally in this driver.

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