edac: fix enabling of polling cell module

The edac driver on cell turned out to be not enabled because of a missing
op_state.  This patch introduces it.  Verified to work on top of Ben's
next branch.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Jens Osterkamp <jens@linux.vnet.ibm.com>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Doug Thompson <dougthompson@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>