This tries to fix spufs so we have an interface closer to what is
specified in the man page for events returned in the third argument of
spu_run.

Fortunately, libspe has never been using the returned contents of that
register, as they were the same as the return code of spu_run (duh!).

Unlike the specification that we never implemented correctly, we now
require a SPU_CREATE_EVENTS_ENABLED flag passed to spu_create, in
order to get the new behavior. When this flag is not passed, spu_run
will simply ignore the third argument now.

Signed-off-by: Arnd Bergmann <arnd.bergmann@de.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>