Bluetooth: Fix missing hdev locking in smp_cmd_ident_addr_info

The hdev lock must be held before calling into smp_distribute_keys. Also
things such as hci_add_irk() require the lock. This patch fixes the
issue by adding the necessary locking into the smp_cmd_ident_addr_info
function.

Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>