Every time a new syscall gets added, a BUILD_BUG_ON in
arch/powerpc/platforms/cell/spu_callbacks.c gets triggered.
Since the addition of a new syscall is rather harmless,
the error should just be removed.

While we're here, add sys_tee to the list and add a comment
to systbl.S to remind people that there is another list
on powerpc.
Signed-off-by: Arnd Bergmann <arnd.bergmann@de.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>