staging: unisys: fix copyright symbol in vbushelper.h

The copyright character in vbushelper.h isn't UTF-8 - swap it out for a
good, old-fashioned (C).

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