powerpc/ps3: Update ps3_defconfig

Refresh ps3_defconfig to latest kernel sources and
change the options:

  CONFIG_PPP=m to CONFIG_PPP=n.
  CONFIG_NAMESPACES=y to CONFIG_NAMESPACES=n
  CONFIG_NUMA=y to CONFIG_NUMA=n

Signed-off-by: Geoff Levand <geoff@infradead.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>