Some of the irq can still be on after a reset or power on as the IP are
powered by the backup power. This could lead to an interrupt dead lock
when the kernel boot. So disable them before booting.

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Cc: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>