staging: unisys: get rid of goto in create_bus_instance()

Remove the unnecessary rc and goto messiness, and just handle freeing
the memory before returning an error in the one place where that needs
to happen.

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