staging: unisys: include: Added kerneldoc comments to visor_device

The visor_device struct is used between multiple drivers, so this
adds kerneldoc comments to the fields.

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