[POWERPC] Cell RAS: Remove DEBUG, and add license and copyright

arch/powerpc/platforms/cell/ras.c still has DEBUG #defined, which is no
longer necessary.  Disable it - this disables two pr_debugs().

While we're there this file should have a copyright notice and license,
so add both.

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>