Bluetooth: Don't bother doing anything if auto_connect doesn't change

When hci_conn_params_set() is called if the new auto_connect value is
the same as the old one we don't need to take any action. Simply return
success from the function in this case.

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