Bluetooth: Serialize sending sendBluetoothServiceUpCallback

In some corner case, Register Adpater and bluetooth service up happen
simultaneously. In such scenario it is possible that bluetooth service
connected message is sent earlier than Register adpater message leading
to callback not sent to client whose registration is still in progress.

Change-Id: I129f841ce28d943c37011932d1b0dbcb58c96422
CRs-Fixed: 2616935
1 file changed