staging: comedi: 8255_pci: initialize MITE data window

According to National Instruments' PCI-DIO-96/PXI-6508/PCI-6503 User
Manual, the physical address in PCI BAR1 needs to be OR'ed with 0x80 and
written to register offset 0xC0 in the "MITE" registers (BAR0).  Do so
during initialization of the National Instruments boards handled by the
"8255_pci" driver.  The boards were previously handled by the
"ni_pcidio" driver, where the initialization was done by `mite_setup()`
in the "mite" module.  The "mite" module comes with too much extra
baggage for the "8255_pci" driver to deal with so use a local, simpler
initialization function.

Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Cc: <stable@vger.kernel.org> # 3.10.y, 3.11.y, 3.12.y, 3.13.y, 3.14.y
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>