iwlwifi: mvm: Fix possible NULL pointer dereference

iwl_mvm_te_clear_data() is called for cleanup in case sending
the HOT_SPOT_CMD failed. However, in case sending the command
caused a fw error and restart (e.g. if the command is not supported)
then the te_data pointer may no longer be valid, which leads to
a NULL pointer dereference.

Fix it by checking that the te_data pointer is not NULL before
dereferencing it.
Signed-off-by: Avraham Stern <avraham.stern@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>

drivers/net/wireless/intel/iwlwifi/mvm/time-event.c

@@ -85,7 +85,7 @@ void iwl_mvm_te_clear_data(struct iwl_mvm *mvm,
 {
 	lockdep_assert_held(&mvm->time_event_lock);
 
-	if (!te_data->vif)
+	if (!te_data || !te_data->vif)
 		return;
 
 	list_del(&te_data->list);