ASoC: msm: qdsp6v2: check if index is out of range before use

Index can be assigned as -EINVAL which could be
out of array index. Check if index is valid value
before use.

CRs-Fixed: 1046606
Change-Id: Ib1af53ab52a65cca2ed9b3489359813e690b1cd6
Signed-off-by: Meng Wang <mwang@codeaurora.org>