EDAC, altera: Add ECC Manager IRQ controller support

To better support child devices, the ECC manager needs to be
implemented as an IRQ controller.

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/1465331757-10227-1-git-send-email-tthayer@opensource.altera.com


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