staging: unisys: shrink the name of a variable

The field debugfs_client_bus_info can be reduced to debugfs_bus_info.
The word client is extraneous in this context.

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>