Bluetooth-OPP: Update OPP RxTx notification during BT turned OFF

This change will ensure that update OPP Rx and Tx notifications
simultaneously while BT is turned OFF. Otherwise, during Rx and Tx
operation while BT is turned OFF only one notification status is
updated.

CRs-Fixed: 609292
Change-Id: Iac4641bce458569e78b36bcbfd9eeb8212fb145f