EDAC, altera: Check parent status for Arria10 EDAC block

In preparation for the Arria10 ECC modules, check the status of the
parent in the device tree to ensure the block is enabled. Skip if no
parent phandle is set in the device tree.

Signed-off-by: Thor Thayer <tthayer@opensource.altera.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-edac <linux-edac@vger.kernel.org>
Link: http://lkml.kernel.org/r/1466603939-7526-2-git-send-email-tthayer@opensource.altera.com


Signed-off-by: Borislav Petkov <bp@suse.de>