Bluetooth: Move SMP initialization after HCI init

First of all, it's wasteful to initialize SMP if it's never going to be
used (e.g. on non-LE controllers). Second of all, when we move to use
l2cap_chan we need to know the real local address, meaning we must have
completed at least part of the HCI init. This patch moves the SMP
initialization to after the HCI init procedure and makes it depend on
whether the controller actually supports LE.

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