hal: Fix arguments passed to set_echo_reference

* set_echo_reference function takes (struct audio_device *, bool) but is
  being passed (struct mixer *, int) instead.

Change-Id: I3b4fab2b2d266eebac0d5bab80f7a377d442d8fa
Merge pull request #4 from CyanogenMod/cm-11.0

hal: Fix arguments passed to set_echo_reference