iwlwifi: mvm: always reconfigure last MCC on init

Currently the last found MCC is reconfigured only in the recovery flow.
But it should always be used when available, for the ifdown/up or
RF-Kill/CT-Kill scenarios.
While at it, fix a couple of bugs in the init-from-last-MCC flow. Return
an error value when a current MCC is not found. Pass on the regdomain to
cfg80211 only if it was changed and don't ignore the return value from
the cfg80211-setter function.

Signed-off-by: Arik Nemtsov <arikx.nemtsov@intel.com>
Reviewed-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>