MAINTAINERS: Update PPC 8xx entry

Not involved in 8xx activities for years, update MAINTAINERS
to reflect it.
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: NScott Wood <scottwood@freescale.com>

MAINTAINERS

@@ -5398,7 +5398,6 @@ F:	arch/powerpc/*/*/*virtex*
 
 LINUX FOR POWERPC EMBEDDED PPC8XX
 M:	Vitaly Bordug <vitb@kernel.crashing.org>
-M:	Marcelo Tosatti <marcelo@kvack.org>
 W:	http://www.penguinppc.org/
 L:	linuxppc-dev@lists.ozlabs.org
 S:	Maintained