Bluetooth: Fix missing break in hci_cmd_complete_evt

Command complete event for HCI_OP_USER_PASSKEY_NEG_REPLY would result
in calling handler function also for HCI_OP_LE_SET_SCAN_PARAM. This
could result in undefined behaviour.

Signed-off-by: Szymon Janc <szymon.janc@tieto.com>
Signed-off-by: Gustavo Padovan <gustavo@padovan.org>