Fix assert when freeing L2CAP flow control credit packets

The data buffers for the L2CEVT_L2CA_SEND_FLOW_CONTROL_CREDIT and
L2CEVT_L2CAP_RECV_FLOW_CONTROL_CREDIT packets do not need to be
freed.

Test: Run new SL4A Test for Connection-oriented channel
Bug: 69859537
Change-Id: Ice412a1c7f0a9b413376438a9fa34cf3f91482af