ASoC: msm-lsm-client: use kzalloc instead of kmalloc

In the ioctl function, driver allocates memory to store data
internally before calling copy_to_user to copy data to user-space.
It is possible that kernel internal information can be leaked to
user space through this if the allocated memory is not completely
overwritten with valid data. Use kzalloc to fix this.

CRs-fixed: 2026045
Change-Id: I754ae2157034a135aaca4a15badf10d2567b7ed6
Signed-off-by: Bhalchandra Gajare <gajare@codeaurora.org>