Bluetooth: Handle CHLD cmd properly incase of Held call

This change will handle the CHLD command properly incase of
Incomming call when there is already active Held call.

Change-Id: Iccb059d71fafb6f4fa3195b8393b8462e4bcff32
Merge "Bluetooth: Handle CHLD cmd properly incase of Held call" into kitkat