ASoC: qdsp6v2: Add error check for pointer and array index

Add NULL check for the pointer to make sure memory is
allocated. Add array boundary check for the index
before using the same array.

Change-Id: Ifd35ca0c0a1cbeee18d7797ea6b43ea31be0eeba
Signed-off-by: Viraja Kommaraju <virajak@codeaurora.org>