staging: unisys: simplify destroy_bus() in uislib.c

The destroy_bus() function is heavily indented and many lines extend past the
right margin. This patch simplifies the function without changing its effects.

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