staging: unisys: visorbus: update comment

Comment was outdated and did not reflect what was actually happening.
Update the comment to reflect reality.

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>