ASoC: msm: qdsp6v2: set pointer to NULL after free

Unsanitized pointer after kfree leads to potential risk.
Set pointer to NULL.

CRs-Fixed: 2008031
Change-Id: Ia59a57fcd142a6ed18d168992b8da4019314afa4
Signed-off-by: Xiaojun Sang <xsang@codeaurora.org>
4 files changed