audio: Enhance virutal input device to support A2DP FM RX

- Add AUDIO_DEVICE_IN_FM_RX_A2DP to APM_AUDIO_IN_DEVICE_VIRTUAL_ALL
  to support FM recording with A2DP headset.

Change-Id: I64091235e52769418e734308be260d8f4c81ae90
CRs-Fixed: 581377
Merge "audio: Enhance virutal input device to support A2DP FM RX"