staging: comedi: ni_pcimio: add routes for NI PCIe-6251 and PCIe-6259

staging: comedi: ni_pcimio: add routes for NI PCIe-6251 and PCIe-6259

We do not currently provide routing information for NI PCIe-6251 and
PCI-6259 boards, but they are functionally identical to the PCI-6251 and
PCI-6259 boards and can share their routing information.  (This has been
confirmed for the PCIe-6251 by Éric Piel, using the "NI MAX" software
for Windows.  It is hoped that it applies to PCIe-6259, but has not yet
been checked due to lack of hardware.)  Initialize the `alt_route_name`
member of the board information for PCIe-6251 and PCIe-6259 to allow
them to make use of the routing information provided for PCI-6251 and
PCI-6259 respectively.

Cc: Éric Piel <piel@delmic.com>
Cc: Spencer E. Olson <olsonse@umich.edu>
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Link: https://lore.kernel.org/r/20200207151400.272678-5-abbotti@mev.co.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>