int suspend_save_image ( void);
IRQs are re-enabled here so we can resume devices and safely write to the swap devices. We disable them again before we leave.
The second lock_swapdevices will unlock ignored swap devices since writing is finished. It is important _NOT_ to umount filesystems at this point. We want them synced (in case something goes wrong) but we DO not want to mark
it is not. (And it does not matter, if we resume correctly, we'll mark system clean, anyway.)