Fm: add null check for Receiver before issuing command

this case happens where call is active and fm is stopped,
soon after this if onAudioFocusChange dispatch to fm, then
while handling focus change we should issue command only
if Receiver is available.

CRs-Fixed: 2479379
Change-Id: I0d950dfc27a87c588c0fe0367c914cab5c06555d
1 file changed
tree: bae16c442e924875891dc308b40c0a49d9353e78
  1. fm_hci/
  2. fmapp2/
  3. helium/
  4. jni/
  5. qcom/