[POWERPC] PS3: Fix sparse warnings

Fix some PS3 build warnings reported by `make C=1'.  You need to
install sparse:
  git://git.kernel.org/pub/scm/devel/sparse/sparse.git



Signed-off-by: Geert Uytterhoeven <Geert.Uytterhoeven@sonycom.com>
Signed-off-by: Geoff Levand <geoffrey.levand@am.sony.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>