staging: unisys: Prep for removing 'info' structs

The visorbus driver has three _info structs lying around
(device, bus, channel) that store subsets of info from the
bigger structs.

Having these structs around make resource handling very difficult
and more complicated than it needs to be.  Use the device
infrastructure and instead pass 'struct visor_device' all
over the place.

In order to do that 'struct visor_device' needs to get smarter.
This patch adds the pieces to prep for it.  The new elements
will be used in later patches.

Signed-off-by: Don Zickus <dzickus@redhat.com>
Signed-off-by: Benjamin Romer <benjamin.romer@unisys.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>