msm: audio: qdsp6v2: Add NULL checking for input parameters

Add checking for NULL. Two parameters shouldn't be NULL.

Change-Id: Ied9e9e6238f6498305844bf3a08370c7cf751fc7
Signed-off-by: Fred Oh <fred@codeaurora.org>

Conflicts:

	arch/arm/mach-msm/qdsp6v2/audio_utils_aio.c