iwlwifi: mvm: simplify iwl_mvm_send_lq_cmd

Remove the flags parameter which should be set to sync or async
according to whether this is called during sta init or not.

Signed-off-by: Eyal Shapira <eyal@wizery.com>
Reviewed-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>