bluetooth: correct `bt_le_scan_param` scan type

The `type` parameter of `struct bt_le_scan_param` is documented as
taking a `BT_LE_SCAN_TYPE_*` value, not a `BT_HCI_LE_SCAN_*` value.

In practice this makes no difference as the values are defined as the
same integer, but does result in `<zephyr/bluetooth/hci.h>` not needing
to be included.

Signed-off-by: Jordan Yates <jordan@embeint.com>