Bluetooth: MGMT: Mark LL Privacy as stable

This marks LL Privacy as stable by removing its experimental UUID and
move its functionality to Device Flag (HCI_CONN_FLAG_ADDRESS_RESOLUTION)
which can be set by MGMT Device Set Flags so userspace retain control of
the feature.

Link: https://github.com/bluez/bluez/issues/1028


Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>