libalsa-int: Check for valid mixer control

 When the mixer value is NULL , the mixer_close function
 Added a check to make sure that only a valid mixer function
 is handled

 CRs-Fixed: 516186
Change-Id: I61a45e4fbc68fbd82fdcb8f372e5b66a36487f2f
1 file changed
tree: 3527e0aff3b1534b364f070dba3c5534ce7d9ed5
  1. alsa_sound/
  2. audiod/
  3. libalsa-intf/
  4. mm-audio/
  5. msm7x30/
  6. msm8660/