mfd: arizona: Disable interrupts during suspend

We aren't able to handle interrupts after the device has suspended since
we need to runtime resume it in order to do so but the controller may not
be available any more. Handle this in the same way as we handle a similar
issue on resume.

Reported-by: Chuansheng Liu <chuansheng.liu@intel.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>