iwlwifi: mvm: don't restart HW if suspending fails before D3 image is loaded

If we haven't loaded the D3 image yet and a failure in the suspend
process occurs, we shouldn't restart the HW, because we're still
running the D0 image.

Signed-off-by: Luciano Coelho <luciano.coelho@intel.com>
Reviewed-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>