staging: unisys: visorbus: Reorder functions to avoid including header

Visorchannel does not need to include visorbus_private.h; all it was
using it for was function prototypes. A simple reorder causes it to
no longer need to include it.

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