EDAC, altera: Disable IRQs while injecting SDRAM errors

Disable IRQs while injecting SDRAM errors. The RT patches exposed
a spinlock deadlock where the spinlock taken for the regmap write
deadlocked with the IRQ clear regmap write.

Error injection is not normally enabled for ECC but only for testing.

Signed-off-by: Thor Thayer <tthayer@opensource.altera.com>
Cc: linux-edac <linux-edac@vger.kernel.org>
Link: http://lkml.kernel.org/r/1476906827-9412-1-git-send-email-tthayer@opensource.altera.com


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