Bluetooth: Use fixed-size preambles

Test: Bluetooth turns on/off finds devices in Settings
Change-Id: Id640f3dbde3f53b31ce62eccf59bbc8d25130388
diff --git a/bluetooth/1.0/default/vendor_interface.h b/bluetooth/1.0/default/vendor_interface.h
index 450b99c..d528a3f 100644
--- a/bluetooth/1.0/default/vendor_interface.h
+++ b/bluetooth/1.0/default/vendor_interface.h
@@ -64,6 +64,7 @@
   enum HciParserState { HCI_IDLE, HCI_TYPE_READY, HCI_PAYLOAD };
   HciParserState hci_parser_state_{HCI_IDLE};
   HciPacketType hci_packet_type_{HCI_PACKET_TYPE_UNKNOWN};
+  uint8_t hci_packet_preamble_[HCI_PREAMBLE_SIZE_MAX];
   hidl_vec<uint8_t> hci_packet_;
   size_t hci_packet_bytes_remaining_;
   size_t hci_packet_bytes_read_;