staging: unisys: include: removed unused 'visor_device.description'

The 'description' variable in visor_device was added in preparation for
removing the 'device_info' struct when the uislib files were removed.

That attribute is never accessed nor set, and the 'name' attribute
provides enough information to correctly identify the driver, it is not
needed.

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>