staging: unisys: removed 'visor_device.devnodes' field

The 'visor_device.devnodes' field was used for displaying driver version
information through the devmajorminor sysfs attribute, which has recently
been removed, rendering the field unnecessary.

Signed-off-by: Alexander Curtin <alexander.curtin@unisys.com>
Signed-off-by: David Kershner <david.kershner@unisys.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>