ASoC: qcom: qdsp6v2: update sanity check

Pointers should be checked for sanity before accessing them.
Change ensures that the sanity of the pointer is checked before
accessing it.

CRs-fixed: 682512
Change-Id: I6b7e97ecfa8cc960db1bdf1c557b3b76dca8a658
Signed-off-by: Gopikrishnaiah Anandan <agopik@codeaurora.org>