Fix crash in l2c_rcv_acl_data during LE CoC SL4A Test

When the incoming ACL messages is not setup yet, we should not further
processed it after we queue it. Otherwise, we will get be accessing the
null data structure for the connection.

Bug: 74240858
Test: Run SL4A test: act.py -c $MY_SL4A_CONFIG -tc BleCocTest:test_coc_secured_connection_throughput
Change-Id: I12e6d5dd30f05a74807afe6b4af1b9599c59886a