msm: audio: qdsp6v2: memeset msm_audio_stats to zero

memeset msm_audio_stats to zero before copying to user space.

Change-Id: I5f47bf85e36d46f726dddae68962a3d1cd06213b
CRs-fixed: 549307
Signed-off-by: Kiran Kandi <kkandi@codeaurora.org>