EDAC, ppc4xx: Access mci->csrows array elements properly

EDAC, ppc4xx: Access mci->csrows array elements properly

The commit

  de3910eb79ac ("edac: change the mem allocation scheme to
		 make Documentation/kobject.txt happy")

changed the memory allocation for the csrows member. But ppc4xx_edac was
forgotten in the patch. Fix it.

Signed-off-by: Michael Walle <michael@walle.cc>
Cc: <stable@vger.kernel.org>
Cc: linux-edac <linux-edac@vger.kernel.org>
Cc: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
Link: http://lkml.kernel.org/r/1437469253-8611-1-git-send-email-michael@walle.cc
Signed-off-by: Borislav Petkov <bp@suse.de>