Bluetooth: Remove unnecessary hdev locking in smp.c

Now that the SMP related key lists are converted to RCU there is nothing
in smp_cmd_sign_info() or smp_cmd_ident_addr_info() that would require
taking the hdev lock (including the smp_distribute_keys call). This
patch removes this unnecessary locking.

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