net: samples: Remove CONFIG_NET_L2_BT_ZEP1656

CONFIG_NET_L2_BT_ZEP1656 should only be used with older Linux up to
4.11 which by now should have been updated in all distros.

For those sticking with older distros should select it manually as
it does breaks IID address it should never be used in production.

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