kernel: Bluetooth: hci_conn: Fix UAF in hci_enhanced_setup_sync

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hciconn: Fix UAF in hcienhancedsetupsync This checks if the ACL connection remains valid as it could be destroyed while hcienhancedsetupsync is pending on cmdsync leading to the following trace: BUG: KASAN:...