wifi: iwlwifi: mvm: Add an add_interface() callback for mld mode

wifi: iwlwifi: mvm: Add an add_interface() callback for mld mode

As the MLD mode and its new APIs are introduced,
we've decided to add a new ieee80211_ops dedicated for
MLD callbacks. Add the MLD add_interface() callback
which uses the new MLD APIs added the previous patches.

Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
Link: https://lore.kernel.org/r/20230314194113.6adc29bff39b.I97ed469028009be9392dcc6f7b5ffbe45f4b2c43@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>