Bluetooth: Send OK response to AT+CREG? command

Found one IOT issue carkit is delaying to issue AT+CHUP command since
it is waiting for OK response code for CREG At command send.

CRs-Fixed: 486532
Change-Id: I718097a57a82db450575317440244d4e3166bf37
Bluetooth: Disallow unnecessary sco fallback.

Due to timing issue, call to close the mConnectScoThread while
audio is just connected was treated as failed case of SCO
connection and we were retrying SCO again even though it was not
required for devices supporting codec.This change will not allow
codec negotiation and further audio on when such timing error
happens.

CRs-Fixed: 494540
Change-Id: I5860bd3dd6672f32a97e2953b4966a5a7e8f7ee9
Merge "Bluetooth: Disallow unnecessary sco fallback."
Merge "Bluetooth: Send OK response to AT+CREG? command"
Merge remote-tracking branch 'caf/jb_2.5' into cm-10.1