staging: unisys: include: Remove unnecessary forward declaration

The struct visor_device had a forward declaration that was not needed.
Remove it.
Reviewed-by: Sameer Wadgaonkar <sameer.wadgaonkar@unisys.com>
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>

drivers/staging/unisys/include/visorbus.h

@@ -39,7 +39,6 @@
 
 #include "channel.h"
 
-struct visor_driver;
 struct visor_device;
 extern struct bus_type visorbus_type;