[POWERPC] spufs: fix signal2 file to report signal2

This fixes the /signal2 file to actually give signal2 data.

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