ASoC: msm: qdsp6v2: Do not free memory that has not been unmapped from DSP

The memory that is not unmapped from DSP should not be used until
DSP clears it. Do not free ion memory if the DSP unmap has
failed.

Change-Id: If6fecb0ad8eb8ddab2e1c6bf4b526ec069555d84
Signed-off-by: Chaithanya Krishna Bacharaju <chaithan@codeaurora.org>